九州大学 研究者情報
論文一覧
田中 敬二(たなか けいじ) データ更新日:2019.06.24

教授 /  工学研究院 応用化学部門 応用精密化学


原著論文
1. Manabu Inutsuka, Masayuki Haraguchi, Masaaki Ozawa, Norifumi L. Yamada, Keiji Tanaka, Adhesion Control of Elastomer Sheet on the Basis of Interfacial Segregation of Hyperbranched Polymer, ACS Macro Letters, 10.1021/acsmacrolett.8b00971, 8, 3, 267-271, 2019.03, [URL], Adhesion of a model rubbery material, cross-linked poly(dimethylsiloxane) (PDMS), onto a solid surface was studied by sum-frequency generation spectroscopy and X-ray photoelectron spectroscopy. To do so, here, we have focused on the adhesive deposit and insoluble layer. The former and latter were defined as the residual amount on the substrate after the peeling and residual layer after washing with a good solvent, respectively. The peel strength of a PDMS sheet adhered onto a glass plate increased with the contact time. Both adhesive deposit and insoluble layer also exhibited comparable contact time dependence. Once a hyperbranched polymer (HBP), which was segregated to the adhesive interface, was incorporated into PDMS, the peel strength and adhesive deposit decreased, although the thickness of the insoluble layer remained almost unchanged. These results suggest that the formation of loosely adsorbed chains on the solid surface, which possess not only trains but also many loop portions and tail parts, plays an important role in the macroscopic adhesion behavior of the PDMS sheet and the interfacial segregation of HBP can prevent it..
2. Mika Aoki, Atsuomi Shundo, Riichi Kuwahara, Satoru Yamamoto, Keiji Tanaka, Mesoscopic Heterogeneity in the Curing Process of an Epoxy-Amine System, Macromolecules, 10.1021/acs.macromol.8b02416, 52, 5, 2075-2082, 2019.03, [URL], Epoxy resins are composed of a three-dimensional network formed by chemical reactions between epoxy and amino compounds, which plays an important role in the mechanical properties. Thus, to use epoxy resins in various applications, it is necessary to gain a better understanding of their network structure. Here, we study the structural heterogeneity evolved in an epoxy-amine mixture during the curing process on the basis of a particle tracking technique, in which the thermal motion of probe particles in the mixture was tracked, small-angle X-ray scattering measurements in conjunction with coarse-grained molecular dynamics simulation. The heterogeneous environment was generated even at the initial stage of the curing process. Notably, the characteristic length scale was on the order of several hundreds of nanometers down to several tens of nanometers, depending on the extent of curing. Once a reaction occurs between a pair of epoxy and amino groups, the temperature at the site is locally elevated due to the heat of formation, accelerating a subsequent reaction nearby. Repeating such a situation, actively and scarcely reacted domains are formed. This is the main origin of the structural heterogeneity in epoxy resins..
3. Mika Aoki, Atsuomi Shundo, Kenji Okamoto, Tatsuya Ganbe, Keiji Tanaka, Segregation of an Amine Component in a Model Epoxy Resin at a Copper Interface, Polymer Journal, 10.1038/s41428-018-0129-4, 51, 3, 359-363, 2019.03, [URL], Epoxy resins, which are obtained by the curing reaction of epoxy- and amine-compounds mixture, have been often utilized in contact with metals. We herein report on the chemical composition of the epoxy resin in close proximity to the copper interface on the basis of a non-destructive method. The concentration of the amine component in the interfacial region was 2-fold higher than that in the bulk, and the interfacial enrichment extended over at least 10 nm. [Figure not available: see fulltext.]..
4. Kentaro Yamamoto, Daisuke Kawaguchi, Kazuki Sasahara, Manabu Inutsuka, Satoru Yamamoto, Kiminori Uchida, Kazuki Mita, Hiroki Ogawa, Mikihito Takenaka, Keiji Tanaka, Aggregation States of Poly(4-methylpentene-1) at a Solid Interface, Polymer Journal, 10.1038/s41428-018-0134-7, 51, 2, 247-255, 2019.02, [URL], A thin film of poly(4-methylpentene-1) (P4MP1) was prepared on a quartz substrate, which was a model system of an interface in filler-reinforced semicrystalline polymer composites. Grazing-incidence wide-angle X-ray diffraction measurements revealed that P4MP1 in the thin film after isothermal crystallization formed a Form I crystal polymorph composed of a tetragonal unit cell with a 72 helix, in which the chain axis was oriented along the direction parallel to the quartz interface. Combining sum-frequency generation vibrational spectroscopy with molecular dynamics simulation enabled us to gain access to the local conformation of P4MP1 chains at the quartz interface and the changes that occurred with isothermal crystallization. Finally, the way in which the initial chain orientation at the substrate interface impacted the crystalline structure in the thin film was discussed..
5. Masayasu Totani, Ling Liu, Hisao Matsuno, Keiji Tanaka, Design of a Star-like Hyperbranched Polymer Having Hydrophilic Arms for Anti-biofouling Coating, Journal of Materials Chemistry B, 10.1039/c8tb03104e, 7, 7, 1045-1049, 2019.01, [URL], A star-like hyperbranched polymer having hydrophilic poly(ethyleneoxide acrylate) arms (HB-PEO9A) was prepared by a core-first method based on atom transfer radical polymerization. The PEO9A layer coated on a solid substrate was dissolved by water, and effectively inhibited protein adsorption and cell adhesion..
6. Ramireddy Boppella, Filipe Marques Mota, Ju Won Lim, Saji Thomas Kochuveedu, Sunghyun Ahn, Jiseok Lee, Daisuke Kawaguchi, Keiji Tanaka, Dong Ha Kim, Plasmon and Upconversion Mediated Broadband Spectral Response in TiO
2
Inverse Opal Photocatalysts for Enhanced Photoelectrochemical Water Splitting, ACS Applied Energy Materials, 10.1021/acsaem.9b00469, 2019.01, [URL], Harvesting low-energy photons by strategically exploiting the photocatalytic properties of plasmonic and upconversion nanocomponents is a promising route to improve solar energy utilization. Herein, a rationally designed 3D composite photoanode integrating NIR-responsive upconversion nanocrystals (UCNs) and visible-responsive plasmonic Au nanoparticles (NPs) into 3D TiO
2
inverse opal nanostructures (Au/UCN/TiO
2
) has been shown to extend the solar energy utilization in the UV-vis-NIR range. The NIR-responsive properties of NaYF
4
:Yb
3+
-based UCNs doped with Er
3+
or Tm
3+
ions, and the effect of an alternating sequential introduction of UCN and Au, have been assessed. With an extended overlap between the emission of Er-UCN and the characteristic SPR band of Au, our ternary Au/Er-UCN/TiO
2
hybrid nanostructure unveiled a notable 10-fold improvement in photocurrent density under UV-vis-NIR illumination compared with a pristine TiO
2
reference. The Au incorporation was confirmed to play a key role in enhancing the efficiency of light harvesting and to synergistically facilitate the energy transfer from UCNs to TiO
2
. This work further dissected plausible mechanistic pathways combining collected photoelectrocatalytic results, with electrochemical impedance measurements and transient absorption spectroscopic measurements. The synthesis and catalytic performance of our Au/UCN/TiO
2
and the underlying mechanism here proposed are expected to reflect extended applicability in analogous applications for efficient solar-to-energy sustainable platforms..
7. Yudai Ogata, Tatsuki Abe, Shigeki Yonemori, Norifumi L. Yamada, Daisuke Kawaguchi, Keiji Tanaka, Impact of the Solid Interface on Proton Conductivity in Nafion Thin Films, Langmuir, 10.1021/acs.langmuir.8b03396, 34, 50, 15483-15489, 2018.12, [URL], Proton conductivity of polyelectrolytes in the interfacial region with a solid is key to the performance of polyelectrolyte-based fuel cells. The proton conductivity of Nafion thin films was examined as a function of the thickness along both directions, normal and parallel to the interface. Neutron reflectivity measurements revealed that a water-containing multilamellar structure was formed at the substrate interface. The presence of the interfacial layer, or the two-dimensional proton-conductive pathway, suppressed and enhanced the out-of-plane and in-plane proton conductivities, respectively. The method of proton conductivity in the interfacial region differed from that in the bulk, namely, the Grotthuss mechanism. Using laminated films, we conclude by showing that the proton conductivity in the Nafion thin film changes on the basis of the interface-to-volume ratio. This knowledge will be helpful for the design of devices containing polyelectrolytes with solid materials..
8. Hung K. Nguyen, Manabu Inutsuka, Daisuke Kawaguchi, Keiji Tanaka, Direct Observation of Conformational Relaxation of Polymer Chains at Surfaces, ACS Macro Letters, 10.1021/acsmacrolett.8b00411, 7, 10, 1198-1202, 2018.10, [URL], Sum-frequency generation spectroscopy was employed to follow the conformation evolution of polystyrene chains at the surface of a spin-coated film in a temperature-ramping mode as well as under isothermal annealing. The conformation of surface chains in an as-cast film was observed to be in a nonequilibrium state, in accordance with reported results for polymer chains in thin spin-coated films. While the relaxation of surface nonequilibrium chains was induced by the enhanced surface mobility, the whole chain motion such as reptation might be a key factor in determining the time scale for equilibrating the surface chain conformation..
9. Hoyeon Kim, Daisuke Kawaguchi, Keiji Tanaka, Yongsok Seo, Fracture Mechanism Change at a Heterogeneous Polymer-Polymer Interface Reinforced with in Situ Graft Copolymers, Langmuir, 10.1021/acs.langmuir.8b01860, 34, 37, 11027-11033, 2018.09, [URL], Dynamic secondary-ion mass spectroscopy (DSIMS) was used to investigate the change in the failure mechanism at a heterogeneous polymer-polymer interface (polystyrene (PS)/polyamide (nylon 6, Ny6)) reinforced with in situ graft copolymers produced by the reaction between Ny6 molecules and poly(styrene-co-maleic anhydride) at the interface. The variation in fracture toughness with bonding time and temperature has been explained by two different failure mechanisms: adhesive failure at the interface for short bonding times and when the bonding temperature is low and cohesive failure between chains at the interface and bulk PS for longer bonding times and when the bonding temperature is high. DSIMS results provide the direct experimental evidence that the nonreactive molecules (PS) diffuse away from the high-potential interface, which induces the cohesive failure in the bulk of the nonreactive molecules (PS) after long annealing times. The change in the adhesion strength with temperature could also cause a change in the failure mechanism. Common features of the fracture mechanisms at heterogeneous interfaces reinforced by the in situ graft copolymers are outlined, which are independent of the polymer crystallinity..
10. Shinichiro Shimomura, Hisao Matsuno, Yohei Kinoshita, Satoshi Fujimura, Keiji Tanaka, Cellular Behaviors on Polymeric Scaffolds with 2D-patterned Mechanical Properties, Polymer Journal, 10.1038/s41428-018-0043-9, 50, 8, 737-743, 2018.08, [URL], We propose a novel concept for cellular scaffolds with 2D-patterned mechanical properties. Thin films of glassy polystyrene (PS) with thicknesses ranging from 100 nm to 1 μm were prepared on epoxy resin-based line and space (L&S) patterned substrates. Although the outermost surface of PS on the L- and S-regions was sufficiently flat at the same level, the mechanical responses differed depending on the presence of the underlying resin foundation. The initial cell adhesion and spreading and the proliferation on the scaffolds were affected by the 2D-patterned mechanical properties, that is, cellular behavior was suppressed on mechanically unstable S-regions..
11. Yongming Hong, Yawei Li, Fengliang Wang, Biao Zuo, Xinping Wang, Li Zhang, Daisuke Kawaguchi, Keiji Tanaka, Enhanced Thermal Stability of Polystyrene by Interfacial Noncovalent Interactions, Macromolecules, 10.1021/acs.macromol.8b01012, 51, 15, 5620-5627, 2018.08, [URL], The local conformation of polystyrene (PS) and deuterated PS at the interface with quartz substrates, which were covered with phenyl groups using phenyltrimethoxysilane (PTS) under various conditions, was examined by sum frequency generation spectroscopy. As evidenced by the red-shift of the wavenumber of the v
2
vibration mode for phenyl groups, it was claimed that PTS phenyl groups standing vertically from the quartz surface induced the perpendicular orientation of PS phenyl rings by energetically favorable parallel-displaced π-π interactions at the interface. The local conformation of PS chains strongly anchored onto the substrate by the π-π interactions remained almost unchanged for 48 h even at a temperature 60 K higher than the bulk glass transition temperature. That is, the interfacial π-π interactions facilitated the adsorption of PS chains on the substrate to attain a large enthalpic gain, resulting in significantly slower dynamics of PS chains at the interface. Our results illustrate the importance of the interfacial noncovalent interactions in controlling the structure and dynamics of macromolecular chains at the interface as well as in the thin film geometry..
12. Yuji Matsumoto, Atsuomi Shundo, Masashi Ohno, Nobutomo Tsuruzoe, Masahiro Goto, Keiji Tanaka, Mesoscopic Heterogeneity in Pore Size of Supramolecular Networks, Langmuir, 10.1021/acs.langmuir.8b00641, 34, 25, 7503-7508, 2018.06, [URL], There has been a considerable interest in developing new types of gels based on a network of fibrous aggregate composed of low molecular weight gelators, also known as supramolecular gels (SMGs). Unlike conventional polymer gels with chemical cross-linking, the network formation in SMGs does not involve any covalent bonds. Thus, the network in SMGs has been often regarded as homogenous or less heterogeneous in comparison with that in chemically cross-linked polymer gels. In this study, we have experimentally verified the existence of the network heterogeneity even in SMGs. The thermal motion of probe particles in SMGs, which were prepared from aqueous dispersions of gelators having a different number of peptide residues, PalGH, PalG2H, and PalG3H, was tracked. The gels were spatially heterogeneous in terms of the network pore size, as evidenced by the variation in the particle motion depending on the location, at which a particle existed. With varying particle size, it was found that the characteristic length scale of the heterogeneity was in the order of (sub)micrometers and was smaller in the order of the PalG2H, PalG3H, and PalGH gels..
13. Biao Zuo, Manabu Inutsuka, Daisuke Kawaguchi, Xinping Wang, Keiji Tanaka, Conformational Relaxation of Poly(styrene- co -butadiene) Chains at Substrate Interface in Spin-Coated and Solvent-Cast Films, Macromolecules, 10.1021/acs.macromol.7b02756, 51, 6, 2180-2186, 2018.03, [URL], The local conformation of poly(styrene-co-butadiene) rubber (SBR) chains in direct contact with a quartz substrate was examined by interface-sensitive sum-frequency generation (SFG) spectroscopy. SFG signals, which could be obtained from functional groups only oriented at the interface, were clearly observed for SBR in a film at room temperature which was much higher than the bulk glass transition temperature (Tg). When the film was thermally annealed, SBR chains at the quartz interface changed their conformation to one with a lower energy state, accompanied by the randomization of both the main and side chain parts. The characteristic temperature, at which interfacial chains started to lose their orientations, was much higher than the bulk Tg. Also, the extent found to be more remarkable for the spin-coated film than for the solvent-cast one. This implies that the stress accumulated at the interface, which resulted from the centrifugal force during the spin-coating process, accelerates the mobility of chains there. Finally, the kinetics experiment well supports the slower orientation relaxation at the interface..
14. Hung K. Nguyen, Asuka Konomi, Shin Sugimoto, Manabu Inutsuka, Daisuke Kawaguchi, Keiji Tanaka, Rotational Dynamics of a Probe in Rubbery Polymers Characterized by Time-Resolved Fluorescence Anisotropy Measurement, Macromolecular Chemistry and Physics, 10.1002/macp.201700329, 219, 3, 2018.02, [URL], The rotational relaxation time (τrot) of a fluorescent molecule, coumarin 153 (C153), dispersed in different rubbery polymers is characterized by time-resolved fluorescence anisotropy measurement, and an attempt is made to quantitatively combine it with the segmental relaxation time (τseg) of the corresponding matrix polymer obtained by dielectric relaxation spectroscopy. This study here demonstrates that τseg extrapolated to higher temperatures using the Vogel–Fulcher–Tammann law can be superimposed on τrot, resulting in a single curve. This behavior is common for polymers with different glass transition temperatures such as polyisoprene and acrylonitrile/butadiene copolymer, implying that the rotational dynamics of C153 is a useful tool for the characterization of polymer dynamics..
15. Hidenobu Taneda, Atsuomi Shundo, Hisao Matsuno, Keiji Tanaka, Design of a Well-Defined Polyrotaxane Structure on a Glassy Polymer Surface, Langmuir, 10.1021/acs.langmuir.7b03130, 34, 2, 709-714, 2018.01, [URL], 水界面における高分子鎖のダイナミクスは、生体関連機能の発現において重要な役割を果たすと考えられている。したがって、分子鎖ダイナミクスの制御のための一つの戦略は、ポリマー鎖を環状化合物で包接し、複合体を形成することであるが、そのような検討はこれまでバルク試料に限られていた。本研究では、典型的なガラス状高分子であるポリメタクリル酸メチルの膜を調製し、クリック反応とLangmuir-Blodgett法を組み合わせることで、膜最表面にポリ(エチレンオキシド)(PEO)と-シクロデキストリン(CD)からなるポリロタキサン構造を導入することに成功している。また、水界面でのPEOの熱運動が、CD分子の導入によって抑制され、その結果、タンパク質吸着や血小板接着のような生物学的応答が変化することを始めて示している。.
16. Hisao Matsuno, Shunya Irie, Toyoaki Hirata, Ruriko Matsuyama, Yukari Oda, Hiroyasu Masunaga, Yukiko Seki, Sadahito Aoshima, Keiji Tanaka, Heterogeneous adhesion of cells on polymer surfaces with underlying amorphous/crystalline phases, Journal of Materials Chemistry B, 10.1039/c7tb03250a, 6, 6, 903-907, 2018.01, [URL], Fibroblastic adhesion behaviour on films of a poly[(2-methoxyethyl vinyl ether) (PMOVE)-block-(l-lactic acid) (PLLA)], in which the surface was covered with PMOVE, was studied. Fibroblasts were sufficiently sensitive to identify crystalline/non-crystalline regions existing beneath the surface PMOVE layer..
17. Mani Sen, Naisheng Jiang, Maya K. Endoh, Tadanori Koga, Alexander Ribbe, Atikur Rahman, Daisuke Kawaguchi, Keiji Tanaka, Detlef M. Smilgies, Locally Favored Two-Dimensional Structures of Block Copolymer Melts on Nonneutral Surfaces, Macromolecules, 10.1021/acs.macromol.7b02506, 51, 2, 520-528, 2018.01, [URL], Self-assembly of block copolymers (BCPs) into arrays of well-defined nanoscopic structures has attracted extensive academic and industrial interests over the past several decades. In contrast to the bulk where phase behavior is controlled by the segmental interaction parameter, the total number of segments in BCPs and volume fraction, the morphologies and orientations of BCP thin films can also be strongly influenced by the substrate surface energy/chemistry effect (considered as a "substrate field"). Here, we report the formation of locally favored structures where all constituent blocks coexist side-by-side on nonneutral solid surfaces irrespective of their chain architectures, microdomain structures, and interfacial energetics. The experimental results using a suite of surface-sensitive techniques intriguingly demonstrate that individual preferred blocks and nonpreferred blocks lie flat on the substrate surface and form a two-dimensional percolating network structure as a whole. The large numbers of solid-segment contacts, which overcome a loss in the conformational entropy of the polymer chains, prevent the structure relaxing to its equilibrium state (i.e., forming microdomain structures) even in a (good) solvent atmosphere. Our results provide direct experimental evidence of the long-lived, nonequilibrium structures of BCPs and may point to a new perspective on the self-assembly of BCP melts in contact with impenetrable solids..
18. Shin Sugimoto, Manabu Inutsuka, Daisuke Kawaguchi, Keiji Tanaka, Reorientation Kinetics of Local Conformation of Polyisoprene at Substrate Interface, ACS Macro Letters, 10.1021/acsmacrolett.7b00927, 7, 1, 85-89, 2018.01, [URL], The performance of a polymer composite material, in which inorganic fillers are dispersed, is closely related to the aggregation states and dynamics of polymer chains at the interface with the filler. In this study, the local conformation of polyisoprene (PI) at a quartz substrate interface was studied as a model system for the rubber/filler composite material. PI films were prepared from a toluene solution onto quartz substrates by a spin-coating method. Sum-frequency generation spectroscopy revealed that the local conformation of PI chains at the quartz interface depended on the spinning rate. The tilt angle of methyl groups increased with the rotational speed, probably due to the centrifugal force applied to chains and probably also the evaporation rate of the solvent during the solidification process. This result indicates that the interfacial orientation of PI chains can remain even at room temperature, which is 87 K higher than the bulk glass transition temperature (Tg b). The interfacial orientation disappeared at a temperature approximately 120 K higher than Tg b..
19. Keiji Tanaka, Aggregation states and thermal molecular motion of polymer chains at solid interfaces, Journal of Fiber Science and Technology, 10.2115/fiber.74.P-6, 74, 1, P6-P9, 2018.01, [URL].
20. Atsuomi Shundo, Takuya Yamamoto, Yasuyuki Tezuka, Keiji Tanaka, Load-induced frictional transition for well-defined cyclic self-Assembled monolayers, Toraibarojisuto/Journal of Japanese Society of Tribologists, 63, 4, 248-252, 2018.01, Self-Assembled monolayer (SAM) with amphiphilic linear molecules has been studied as a surface modifier. In general, the surface properties of a SAM are dependent on the chain end chemistry of the molecules. Thus, a SAM composed of alkane loops from cyclic alkanedisulfide on a gold substrate, in which both sulfurs arc bound to gold, may possess unique surface properties due to the chain folding as well as a lack of chain ends. We here focus on the frictional properties of the linear and cyclic SAMs. For the cyclic SAM, the load dependence of the frictional force became more striking beyond a threshold. Such a frictional transition was not observed for the corresponding linear SAM. The load-induced transition in the frictional response from the alkane loops could be related to the conformational change of the alkane loops, which collapsed along the direction normal to the SAM surface..
21. Nozomi Itagaki, Yukari Oda, Toyoaki Hirata, Hung Kim Nguyen, Daisuke Kawaguchi, Hisao Matsuno, Keiji Tanaka, Surface Characterization and Platelet Adhesion on Thin Hydrogel Films of Poly(vinyl ether), Langmuir, 10.1021/acs.langmuir.7b03427, 33, 50, 14332-14339, 2017.12, [URL], Poly(vinyl ether), with short oxyethylene side chains which possess a simple and relatively polar structure, should be a unique candidate for a bioinert material thanks to its solubility in water. On the basis of living cationic copolymerization and subsequent ultraviolet light irradiation, thin films of poly(2-methoxyethyl vinyl ether) with different cross-linking densities were prepared on solid substrates. The films were thickened in water, and the extent was dependent on the cross-linking density. Although the surface chemistry and aggregation states were almost identical to one another, the stiffness, or the softness, of the outermost region in the film was strongly dependent on the cross-linking density. That is, the interface between polymer and water became thicker, or more diffused, with decreasing cross-linking density. The blood compatibility based on the platelet adhesion on to the hydrogel films was better for a more diffused interface..
22. Deborah A. Barkley, Naisheng Jiang, Mani Sen, Maya K. Endoh, Jonathan G. Rudick, Tadanori Koga, Yugang Zhang, Oleg Gang, Guangcui Yuan, Sushil K. Satija, Daisuke Kawaguchi, Keiji Tanaka, Alamgir Karim, Chain Conformation near the Buried Interface in Nanoparticle-Stabilized Polymer Thin Films, Macromolecules, 10.1021/acs.macromol.7b01187, 50, 19, 7657-7665, 2017.10, [URL], It is known that when nanoparticles are added to polymer thin films, they often migrate to the film-substrate interface and form an "immobile interfacial layer", which is believed to be the mechanism behind dewetting suppression. We here report a new mechanism of dewetting suppression from the structural aspect of polymer chains accommodated at the film-substrate interface. Dodecanethiol-functionalized gold (Au) nanoparticles embedded in relatively low molecular weight PS thin films prepared on silicon (Si) substrates were used as a model. We mimicked the previously reported conditions, where the nanoparticles preferentially migrate to the substrate, and successfully stabilized the PS thin films via thermal annealing. A suite of surface-sensitive techniques including atomic force microscopy, grazing incidence small-angle X-ray scattering, X-ray/neutron reflectivity, and sum frequency generation spectroscopy in conjunction with the established solvent leaching process enabled us to unveil the polymer chain conformation and the dispersion structure of the nanoparticles at the film-substrate interface. The results evidenced that thermal annealing promotes irreversible polymer adsorption onto the substrate surface along with the migration of the nanoparticles. In addition, we found that the migration of the nanoparticles causes the changes in the conformations and interfacial orientations of the adsorbed polymer chains compared to those of the adsorbed polymer chains formed in the nanoparticle-free PS thin film. The resultant interfacial polymer structure allows for the interpenetration between free chains and the adsorbed chains, thereby stabilizing the thin film..
23. Kentaro Yamamoto, Tomoyasu Hirai, Yukari Oda, Daisuke Kawaguchi, Hisao Matsuno, Keiji Tanaka, A Polymer Interfacial Modifier Synthesized by Living Anionic Polymerization
Incorporation of Inorganic Blocks to Chain Ends, Macromolecular Chemistry and Physics, 10.1002/macp.201600473, 218, 12, 2017.06, [URL], As a polymer interfacial modifier, poly(methyl methacrylate) (PMMA) terminated with elemental blocks of polyhedral oligomeric silsesquioxane (POSS) has been exploited through the phenomenon of preferential segregation in PMMA films. The modifier synthesized by living anionic polymerization using a bifunctional initiator is segregated at the surface in the mixture of PMMA due to a “buoy” effect of the POSS blocks. This further results in the surface wettability of PMMA being regulated on the basis of the amount of the modifier fed into the matrix. Finally, it is shown that the amount of the modifier in the PMMA films affects the cell proliferation behavior via the wettability. (Figure presented.)..
24. Hung Kim Nguyen, Manabu Inutsuka, Daisuke Kawaguchi, Keiji Tanaka, Depth-resolved local conformation and thermal relaxation of polystyrene near substrate interface, Journal of Chemical Physics, 10.1063/1.4976523, 146, 20, 2017.05, [URL], By means of sum-frequency generation spectroscopy, we report a depth-resolved measurement of the local conformation and chain relaxation of polystyrene (hPS) located at different distances from the quartz interface. To control the distance from the quartz interface, deuterated polystyrene (dPS) layers with thicknesses of 3.4, 7.5, and 20 nm were coated on the quartz substrates. The hPS chains in direct contact with the substrate surface predominantly orient their phenyl rings in a direction normal to the substrate. This conformation was found to be barely relaxed when the film was annealed for 24 h at 423 K, higher than the bulk glass transition temperature. In contrast, for the hPS chains supported on the dPS layer, the orientation of phenyl rings of hPS became weaker with the annealing and this trend was more significant with increasing distance from the quartz substrate. In particular, the orientation of phenyl rings of hPS after annealing vanished at a distance of 20 nm. These results might provide an important evidence of the difference in the relaxation dynamics of the PS chains located at different distances from the quartz interface..
25. Hisao Matsuno, Ryota Tsukamoto, Yukari Oda, Keiji Tanaka, Platelet adhesion on the surface of a simple poly(vinyl ether), polymer, 10.1016/j.polymer.2017.01.036, 116, 479-486, 2017.05, [URL], A better understanding of controlling factors in the control of bio-events on polymer surfaces is the first benchmark toward realization of life innovation. Although it has been accepted that a family of poly(vinyl ether) (PVE) with various side chain structures is a good candidate for a blood compatible material, the reasons are not fully understood. In this study, poly(vinyl ether) with a simple side chain structure, poly(ethyl vinyl ether) (PEVE), was studied. Since the glass transition temperature of PEVE is lower than room temperature, its thin films can be difficult to prepare. Thus, PEVE was mixed with a glassy polymer of poly(p-vinylphenol) (PVPh). The aggregation states of polymer chains and water molecules at the interface were characterized by the interfacial sensitive spectroscopy. The relationship between the structural information and the platelet adhesion behavior is discussed. This leads to a hypothesis that the states of water molecules affect platelet adhesion and activation behaviors on PVE..
26. Tomonori Ono, Kaoru Kawasaki, Keiji Tanaka, Toshihiko Nagamura, Ultrafast photoresponsive materials for all-optical light modulation by polymer thin films, polymer, 10.1016/j.polymer.2017.02.051, 116, 523-533, 2017.05, [URL], Ultrafast and single exponential responsive materials were achieved by encapsulating donor-acceptor linked molecules into cucurbitunitl[8], CB[8], as nanocavity hosts. Various aromatic groups were linked with various types of 4,4′-bipyridinium groups through propyloxy linker. They showed characteristic charge-transfer (CT) absorption with specific colors in aqueous solutions. Upon addition of CB[8], they showed remarkably different colors due to intramolecular CT complex formation in CB[8]. Upon femtosecond laser excitation of CT band extremely fast electron transfer occurred from a donor to an acceptor unit accompanying new absorption in the visible to near-infrared region due mainly to photoreduced bipyridinium derivatives. Thermal back electron transfer reactions in CB[8] were found to follow a single exponential decay with rate constants ranging more than two orders depending on the combination of a donor and an acceptor unit. Their rate constants vs. free energy changes for oxidized donors and reduced acceptors in linked molecules were expressed by the Marcus theory..
27. Shinichiro Shimomura, Hisao Matsuno, Kazuaki Sanada, Keiji Tanaka, Cell Adhesion on Glassy Scaffolds with a Different Mechanical Response, JOURNAL OF MATERIALS CHEMISTRY B, 10.1039/c6tb02617f, 5, 4, 714-719, 2017.03.
28. Biao Zuo, Yue Liu, Yongfeng Liang, Daisuke Kawaguchi, Keiji Tanaka, Xinping Wang, Glass Transition Behavior in Thin Polymer Films Covered with a Surface Crystalline Layer, MACROMOLECULES, 10.1021/acs.macromo1.6b02740, 50, 5, 2061-2068, 2017.03.
29. Atsuomi Shundo, 堀 耕一郎, Yasuyuki Tezuka, Takuya Yamamoto, Keiji Tanaka, Load-Induced Frictional Transition at a Well-Defined Alkane Loop Surface, LANGMUIR, 10.1021/acs.langmuir.6b04042, 33, 9, 2396-2401, 2017.03, 自己組織化単分子膜(SAM)は、材料表面に望みの物性・機能性を与えるための分子ツールとして注目され、実デバイスなどにも広く用いられてきた。しかしながら、これまで、SAM形成は線状分子に限定されており、表面物性・機能性への分子末端の影響が避けられないなどの問題があった。しかしながら、本研究では、環状アルカンジスルフィドを用いることで炭化水素環状鎖からなるSAMを形成することに成功し、表面物性・機能性への分子末端の影響を明確にしている。この結果は、材料表面の物性・機能性設計へ新たな指針を提案するものとして高く評価されている。.
30. Tomonori Iizuka, Yoshito Ohtake, Keiji Tanaka, A synergistic effect of light and heat on degradation for polypropylene, Zairyo/Journal of the Society of Materials Science, Japan, 10.2472/jsms.66.238, 66, 3, 238-243, 2017.03, [URL], Oxidative degradation of polypropylene (PP) is accelerated by not only sunlight but also temperature. Here we propose how the degradation behavior of PP under ultraviolet light irradiation conditions at elevated temperatures, which are more severe than the standards set by the Japanese Industrial Standards (JIS), can be examined. Fourier-transform infrared spectroscopy in conjunction with gel permeation chromatography revealed that the combination of light and heat definitely accelerated the chain scission, or oxidative degradation, of PP, resulting in deterioration of mechanical properties for PP..
31. Biao Zuo, Yue Liu, Yongfeng Liang, Daisuke Kawaguchi, Keiji Tanaka, Xinping Wang, Glass Transition Behavior in Thin Polymer Films Covered with a Surface Crystalline Layer, Macromolecules, 10.1021/acs.macromol.6b02740, 50, 5, 2061-2068, 2017.03, [URL], Thin amorphous poly(ethylene terephthalate) (PET) films covered with/without a crystallized surface layer were prepared onto silicon wafers. In the former and latter cases, the surface mobility in the film was depressed and enhanced, respectively. The glass transition temperature (Tg) of the amorphous PET film decreased with the reduction of the film thickness, exhibiting a remarkable nanoconfinement effect. However, once the surface region of the thin film was crystallized, or frozen in terms of the segmental motion, Tg of the films recovered to that of the bulk. Concurrently, the apparent activation energy of the segmental motion in the surface-crystallized film was in good accordance with the bulk value as well. These results make it clear that the mobility in the surface region plays an essential role in the glass transition of the thin films..
32. 平田 豊章, Hisao Matsuno, Daisuke Kawaguchi, Manabu Inutsuka, Tomoyasu Hirai, Masaru Tanaka, Keiji Tanaka, Dynamics of a bioinert polymer in hydrated states by dielectric relaxation spectroscopy, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 10.1039/c6cp07322k, 19, 2, 1389-1394, 2017.01.
33. Shin Sugimoto, Yukari Oda, 平田 豊章, Ruriko Matsuyama, Hisao Matsuno, Keiji Tanaka, Surface segregation of a branched polymer with hydrophilic poly[2-(2-ethoxy)ethoxyethyl vinyl ether] side chains, POLYMER CHEMISTRY, 10.1039/c6py01984f, 8, 3, 505-510, 2017.01.
34. Yuji Matsumoto, Atsuomi Shundo, Masashi Ohno, Nobutomo Tsuruzoe, Masahiro Goto, Keiji Tanaka, Evolution of heterogeneity accompanying sol-gel transitions in a supramolecular hydrogel, Soft Matter, 10.1039/c7sm01612c, 13, 40, 7433-7440, 2017.01, [URL], When a peptide amphiphile is dispersed in water, it self-assembles into a fibrous network, leading to a supramolecular hydrogel. When the gel is physically disrupted by shaking, it transforms into a sol state. After aging at room temperature for a while, it spontaneously returns to the gel state, called sol-gel transition. However, repeating the sol-gel transition often causes a change in the rheological properties of the gel. To gain a better understanding of the sol-gel transition and its reversibility, we herein examined the thermal motion of probe particles at different locations in a supramolecular hydrogel. The sol obtained by shaking the gel was heterogeneous in terms of the rheological properties and the extent decreased with increasing aging time. This time course of heterogeneity, or homogeneity, which corresponded to the sol-to-gel transition, was observed for the 1st cycle. However, this was not the case for the 2nd and 3rd cycles; the heterogeneity was preserved even after aging. Fourier-transform infrared spectroscopy, small-angle X-ray scattering, and atomic force and confocal laser scanning microscopies revealed that, although the molecular aggregation states of amphiphiles both in the gel and sol remained unchanged with the cycles, the fibril density diversified to high and low density regions even after aging. The tracking of particles with different sizes indicated that the partial mesh size in the high density region and the characteristic length scale of the density fluctuation were smaller than 50 nm and 6 μm, respectively..
35. Shinichiro Shimomura, Hisao Matsuno, Kazuaki Sanada, Keiji Tanaka, Cell adhesion on glassy scaffolds with a different mechanical response, Journal of Materials Chemistry B, 10.1039/c6tb02617f, 5, 4, 714-719, 2017, [URL], L929 mouse fibroblast cells were cultured on bilayer films composed of a glassy poly(methyl methacrylate) (PMMA) on a rubbery polyisoprene. When the thickness of the upper PMMA film fell short of a threshold value of 50 nm, the adhesion of fibroblasts on it was remarkably suppressed. A possible explanation is that the surface of a bilayer with an ultrathin PMMA layer apparently becomes softer due to the manifestation of a mechanical response from the rubbery layer underneath. Finite element analysis shows that the shear stress at the bilayer surface induced by traction force of the attached cells is dependent on the PMMA thickness, similar to the cell adhesion behavior. These results make it clear that fibroblasts can sense the surface stiffness of polymers with a modulus even on the order of MPa..
36. Toyoaki Hirata, Hisao Matsuno, Daisuke Kawaguchi, Manabu Inutsuka, Tomoyasu Hirai, Masaru Tanaka, Keiji Tanaka, Dynamics of a bioinert polymer in hydrated states by dielectric relaxation spectroscopy, Physical Chemistry Chemical Physics, 10.1039/c6cp07322k, 19, 2, 1389-1394, 2017, [URL], The chain dynamics of well-defined poly(2-methoxyethyl acrylate) (PMEA), which has been used in practice as a bioinert coating for heart-lung machines, was examined as a function of water content by dielectric relaxation spectroscopy (DRS). Two relaxation processes observed in both dried and hydrated films were assigned to the segmental motion (α-process) and the relatively smaller scale motion such as the hindered rotation of side chains (β-process). Water molecules adsorbed on PMEA made the α-process faster, meaning that water molecules in PMEA played the role of a plasticizer. Combining the above knowledge with the depth dependence of water content in the PMEA film previously obtained by neutron reflectivity, the segmental dynamics of PMEA at the water interface, which should be crucial to bio-inertness, is discussed. We found that the segmental motion was markedly faster than that in the bulk and almost comparable to the side chain motion..
37. Keiji Tanaka, Structure, physical properties and function of polymers at various interfaces, Sen'i Gakkaishi, 73, 5, 207, 2017.
38. Chien-Chung Shih, Cheng-Yu Chung, Hung-Chin Wu,, Yuma Morimitsu, Hisao Matsuno, Keiji Tanaka, Wen-Chang Chen, Transparent Deoxyribonucleic Acid Substrate with High Mechanical Strength for Flexible and Biocompatible Organic Resistive Memory Devices, ChemComm, 10.1039/c6cc07648c, 52, 92, 13463-13466, 2016.11.
39. Yuma Morimitsu, Hisao Matsuno, Noboru Ohta, Hiroshi Sekiguchi, Keiji Tanaka, Direct Correlation between Molecular Cross-linking and Macroscopic Mechanical Properties for Green Solids of Deoxyribonucleic Acids, CHEMNANOMAT, 10.1002/cnma.201600222, 2, 11, 1023-1027, 2016.11.
40. Shinichiro Shimomura, Manabu Inutsuka, Norifumi L. Yamada, Keiji Tanaka, Unswollen layer of cross-linked polyisoprene at the solid interface, POLYMER, 10.1016/j.polymer.2016.07.047, 105, 526-531, 2016.11.
41. Tomonori Iizuka, Yoshito Ohtake, Keiji Tanaka, A effect of moisture on photo-degradation for polypropylene, Zairyo/Journal of the Society of Materials Science, Japan, 10.2472/jsms.65.812, 65, 11, 812-817, 2016.11, [URL], Photo-degradation of polymers for outdoor use are accelerated by degradation factors such as heat and moisture. Polypropylene(PP) is excellent in water resistance, but is inferior to weatherability. Therefore, in this study, PP was exposed under the water spray condition by using Xenon arc lamp. We evaluated the synergistic effect of light and moisture using the quantification technique of degradation. Results from the Fourier-transform infrared spectroscopic and X-ray Photoelectron Spectroscopy revealed that moisture accelerated the oxidative degradation of PP. In addition, with the progress of the oxidative degradation, melting point and thermal decomposition temperature of PP was lowered. The resulting collapse of crystal structure and chain scission therefore deteriorated the mechanical properties (Charpy impact strength, elongation) of PP..
42. Shinichiro Shimomura, Manabu Inutsuka, Koichiro Tajima, Masaaki Nabika, Satoru Moritomi, Hisao Matsuno, Keiji Tanaka, Stabilization of Polystyrene Thin Films by Introduction of a Functional End Group, POLYMER JOURNAL, 10.1038/pj.2016.58, 48, 9, 949-953, 2016.09.
43. Hisao Matsuno, Ryota Tsukamoto, Yu Kaneshiro, Satoru Yamada, Keiji Tanaka, Platelet Adhesion on Films of Poly(vinylene carbonate) and Its Derivatives, CHEMISTRY LETTERS, 10.1246/cl.160373, 45, 8, 913-915, 2016.08.
44. Atsuomi Shundo, 堀 耕一郎, PENALOZA DAVID JR PENULIAR, Yuji Matsumoto, Yasushi Okumura, Hirotsugu Kikuchi , Kyung Eun Lee, Sang Ouk Kim, Keiji Tanaka, Hierarchical Spatial Heterogeneity in Liquid Crystals Composed of Graphene Oxides, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 10.1039/c6cp03614g, 18, 32, 22399-22406, 2016.08.
45. Kenji Okamoto, Tatsuya Ganbe, Nobuyuki Sekine, Mika Aoki, Manabu Inutsuka, Atsuomi Shundo, Daisuke Kawaguchi, Keiji Tanaka, Nanoscale characterization of epoxy interface on silica, 1st IEEE International Conference on Dielectrics, ICD 2016
Proceedings of the 2016 IEEE International Conference on Dielectrics, ICD 2016
, 10.1109/ICD.2016.7547549, 1, 84-87, 2016.08, [URL], The objective of this study is to carry out nanoscale characterization of the epoxy resin interface on silica by determining the glass-transition temperature (Tg) and molecular conformation at the interface by means of a novel non-destructive method. The Tg was determined by fluorescence lifetime measurements using evanescent wave excitation. It was revealed that the Tg of epoxy resin at a distance of 30 nm from the interface was 10 K higher than that at a distance of 80 nm. The chemical composition and molecular conformation were analysed by X-ray photoelectron spectroscopy and sum-frequency generation (SFG) spectroscopy, respectively. The SFG data revealed that unreacted epoxy group remained at the interface. The Tg of epoxy resin increased in the regions near the interface, and the epoxy group remained unreacted at a distance of ca. 10 nm or less from the interface..
46. Yukari Oda, Cui Zhang, Daisuke Kawaguchi, Hisao Matsuno, Shokyoku Kanaoka, Sadahito Aoshima, Keiji Tanaka, Design of Blood-Compatible Interfaces with Poly(vinyl ether)s, ADVANCED MATERIALS INTERFACES, 10.1002/admi.201600034, 3, 12, 2016.06.
47. Yukari Oda, Cui Zhang, Daisuke Kawaguchi, Hisao Matsuno, Shokyoku Kanaoka, Sadahito Aoshima, Keiji Tanaka, Bio-Inert Surfaces
Design of Blood-Compatible Interfaces with Poly(vinyl ether)s (Adv. Mater. Interfaces 12/2016), Advanced Materials Interfaces, 10.1002/admi.201670058, 3, 12, 2016.06, [URL].
48. Mani Sen, Naisheng Jiang, Justin Cheung, Maya K. Endoh, Tadanori Koga, Daisuke Kawaguchi, Keiji Tanaka, Flattening Process of Polymer Chains Irreversibly Adsorbed on a Solid, ACS MACRO LETTERS, 10.1021/acsmacrolett.6b00169, 5, 4, 504-508, 2016.04.
49. Shinichiro Shimomura, Hisao Matsuno, Toshiyuki Ohta, Seiichi Kawahara, Keiji Tanaka, Initial Adhesion of Fibroblasts on Thin Rubber Scaffolds, CHEMISTRY LETTERS, 10.1246/cl.160061, 45, 4, 475-477, 2016.04.
50. Hisao Matsuno, Ryota Tsukamoto, Shinichiro Shimomura, Tomoyasu Hirai, Yukari Oda, Keiji Tanaka, Platelet-adhesion Behavior Synchronized with Surface Rearrangement in a Film of Poly(methyl methacrylate) Terminated with Elemental Blocks, POLYMER JOURNAL, 10.1038/pj.2015.118, 48, 4, 413-419, 2016.04.
51. Keiji Tanaka, Takeshi Serizawa, Wen Chang Chen, Kookheon Char, Takashi Kato, Special Issue
Polymer surfaces, interfaces and thin films, Polymer Journal, 10.1038/pj.2016.26, 48, 4, 2016.04, [URL].
52. Takehiro Sagawa, Fuyuki Ito, Atsushi Sakai, Yudai Ogata, Keiji Tanaka, Hiroshi Ikeda, Substituent-dependent Backward Reaction in Mechanofluorochromism of Dibenzoylmethanatoboron Difluoride Derivatives, PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES, 10.1039/c5pp00453e, 15, 3, 420-430, 2016.03.
53. Yudai Ogata, Daisuke Kawaguchi, Keiji Tanaka, The Impact of Polymer Dynamics on Photoinduced Carrier Formation in Films of Semiconducting Polymers, JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 10.1021/acs.jpclett.5b02255, 6, 23, 4794-4798, 2015.12.
54. Toyoaki Hirata, Hisao Matsuno, Daisuke Kawaguchi, Norifumi L. Yamada, Masaru Tanaka, Keiji Tanaka, Construction of a Blood-compatible Interface Based on Surface Segregation in a Polymer Blend, POLYMER, 10.1016/j.polymer.2015.10.001, 78, 219-224, 2015.11.
55. Watanabe Motonori, Hidehisa Hagiwara, Yudai Ogata, Aleksandar Tsekov Staykov, Sean R. Bishop, Nicola H. Perry, Yuan Jay Chang, 伊田 進太郎, Keiji Tanaka, Tatsumi Ishihara, Impact of alkoxy chain length on carbazole-based, visible light-driven, dye sensitized photocatalytic hydrogen production, JOURNAL OF MATERIALS CHEMISTRY A, 10.1039/c5ta04991a, 3, 43, 21713-21721, 2015.11.
56. Tisato Kajiyama, Hirohiko Yakabe, Daisuke Kawaguchi, Atsushi Takahara, Keiji Tanaka, Melting Behavior of Thin Polyethylene Films, JOURNAL OF PLASTIC FILM & SHEETING, 10.1177/8756087915594418, 31, 4, 401-413, 2015.10.
57. Keigo Matsumoto, Atsuomi Shundo, Masashi Ohno, Kowichiro Saruhashi, Nobuhide Miyachi, Nobutomo Tsuruzoe, Keiji Tanaka, Sol-gel Transition Accelerated by The Co-assembly of Two Components in Supramolecular Hydrogels, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 10.1039/c5cp04800a, 17, 40, 26724-26730, 2015.10.
58. Manabu Inutsuka, Ayanobu Horinouchi, Keiji Tanaka, Aggregation States of Polymers at Hydrophobic and Hydrophilic Solid Interfaces, ACS MACRO LETTERS, 10.1021/acsmacrolett.5b00592, 4, 10, 1174-1178, 2015.10.
59. F. Chen, D. Peng, Yudai Ogata, Keiji Tanaka, Z. Yang, Yoshihisa Fujii, Norifumi L. Yamada, C. -H. Lam, O. K. C. Tsui, Confinement Effect on the Effective Viscosity of Plasticized Polymer Films, MACROMOLECULES, 10.1021/acs.macromol.5b01780, 48, 20, 7719-7726, 2015.10.
60. Hoyeon Lee, Seongjun Jo, Toyoaki Hirata, Norifumi L. Yamada, Keiji Tanaka, Eunkyoung Kim, Du Yeol Ryu, Interpenetration of Chemically Identical Polymer onto Grafted Substrates, POLYMER, 10.1016/j.polymer.2015.07.054, 74, 70-75, 2015.09.
61. Tomoyasu Hirai, Yukari Oda, David P. Penaloza, Daisuke Kawaguchi, Keiji Tanaka, Control of surface structure and dynamics of polymers based on precision synthesis, Anionic Polymerization
Principles, Practice, Strength, Consequences and Applications
, 10.1007/978-4-431-54186-8_19, 861-880, 2015.09, [URL], Aggregation states and dynamics of polymers at the surface are generally different from those in the corresponding bulk state. To what extent they differ from that of the bulk strongly depends on the polymer primary structure. Therefore, finetuning the surface properties of polymers can be achieved by exhibiting control over their structure using precision polymer synthesis. We here show how the polymer design effectively impacts the structure and dynamics at the surfaces..
62. Toyoaki Hirata, Hisao Matsuno, Daisuke Kawaguchi, Norifumi L. Yamada, Masaru Tanaka, Keiji Tanaka, Effect of Interfacial Structure on Bioinert Properties of Poly(2-methoxyethyl acrylate)/poly(methyl methacrylate) Blend Films in Water, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 10.1039/c5cp01972a, 17, 26, 17399-17405, 2015.07.
63. Hisao Matsuno, Ruriko Matsuyama, Arisa Yamamoto, Keiji Tanaka, Enhanced Cellular Affinity for Poly(lactic acid) Surfaces Modified with Titanium Oxide, POLYMER JOURNAL, 10.1038/pj.2015.30, 47, 7, 505-512, 2015.07.
64. 森賀 俊典, 青山 直揮, 田中 敬二, ウレタンガスケットのシーリング特性に及ぼすR値(NCO基/ OHモル比)の影響, 日本ゴム協会誌, 88, 7, 257-262, 2015.07.
65. Toshinori Moriga, Naoki Aoyama, Keiji Tanaka, Development of a Polyurethane Sealing Gasket with Excellent Sealing and Opening Properties, POLYMER JOURNAL, 10.1038/pj.2015.6, 47, 5, 400-407, 2015.05.
66. Mika Aoki, Daisuke Kawaguchi, Tatsuya Ganbe, Nobuyuki Sekine, Kenji Okamoto, Keiji Tanaka, Glass-transition Temperature Determination for Polymers Using Europium Complex as a Fluorescence Probe, CHEMISTRY LETTERS, 10.1246/cl.150013, 44, 5, 659-661, 2015.05.
67. Yudai Ogata, Daisuke Kawaguchi, Keiji Tanaka, An Effect of Molecular Motion on Carrier Formation in a Poly(3-hexylthiophene) Film, Scientific Reports, 10.1038/srep08436, 5, 8436, 2015.04, 本論文は、ポリ(3-ヘキシルチオフェン)(P3HT)膜の光電荷生成と分子運動について検討したものである。
P3HT 膜に光照射すると、正電荷と負電荷との対が形成された後、自発的に正および負電荷に分離されることを見出した。また、この電荷生成の速度定数は、低温では一定であるが、主鎖のねじれ運動に対応する緩和温度から
温度とともに増加した。
このことから、P3HT膜において分子運動は光電荷生成を支配する因子のひとつであると結論した。.
68. Yukari Oda, Daisuke Kawaguchi, Toyoaki Hirata, Norifumi L. Yamada, Shokyoku Kanaoka, Sadahito Aoshima, Keiji Tanaka, Density Profiles of Well-defined Poly(methyl 2-propenyl ether) (PMPE) Near Water Interface, Macromolecular Symposia, 350, 1, 99-104, 2015.04.
69. Toyoaki Hirata, Hisao Matsuno, Daisuke Kawaguchi, Tomoyasu Hirai, Norifumi L. Yamada, Masaru Tanaka, Keiji Tanaka, Effect of Local Chain Dynamics on a Bioinert Interface, LANGMUIR, 10.1021/acs.langmuir.5b00258, 31, 12, 3661-3667, 2015.03.
70. SIM JAE HYUN, Shuping Dong, Katrin Röemhild, Abdulaziz Kaya, Daewon Sohn, Keiji Tanaka, Maren Roman, Thomas Heinze, Alan R. Esker, 2-Hydroxypropyltrimethylammonium xylan adsorption onto rod-like cellulose nanocrystal, JOURNAL OF COLLOID AND INTERFACE SCIENCE, 10.1016/j.jcis.2014.10.071, 440, 119-125, 2015.02.
71. Cui Zhang, Yukari Oda, Daisuke Kawaguchi, Shokyoku Kanaoka, Sadahito Aoshima, Keiji Tanaka, Dynamic-driven Surface Segregation of a Hydrophilic Component in Diblock Copolymer Films, CHEMISTRY LETTERS, 10.1246/cl.140924, 44, 2, 166-168, 2015.02.
72. Daisuke Kawaguchi, Yohei Tateishi, Keiji Tanaka, Time-Resolved Fluorescence Analysis for Dye-Labeled Polystyrene in Thin Films, Journal of Non-Crystalline Solids, 10.1016/j.jnoncrysol.2014.09.010, 407, 284-287, 2015.01.
73. Keigo Matsumoto, Atsuomi Shundo, Masashi Ohno, Shun Fujita, Kowichiro Saruhashi, Nobuhide Miyachi, Katsuaki Miyaji, Keiji Tanaka, Modulation of Physical Properties of Supramolecular Hydrogels based on a Hydrophobic Core, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 10.1039/c4cp04395b, 17, 3, 2192-2198, 2015.01.
74. Dong Ha Kim, Keiji Tanaka, Juan Peng, A special issue on functional polymeric nanomaterials, Science of Advanced Materials, 10.1166/sam.2015.2274, 7, 5, 827-829, 2015.01, [URL].
75. Yukari Oda, Daisuke Kawaguchi, Toyoaki Hirata, Norifumi L. Yamada, Shokyoku Kanaoka, Sadahito Aoshima, Keiji Tanaka, Density profiles of well-defined poly(methyl 2-propenyl ether) (PMPE) near water interface, Macromolecular Symposia, 10.1002/masy.201400031, 350, 1, 99-104, 2015.01, [URL], Poly(methyl 2-propenyl ether) (PMPE) is structually different in terms of the presence of an α-methyl group on the main chain from poly(vinyl methyl ether) (PVME), the phase behaviors of which have been widely characterized with polystyrene (PS) and water. Due to the incorporation of the α-methyl group, PMPE is immiscible with both PS and water. These results encouraged us to investigate a PMPE/water interface more closely. Thus, the density profiles of PMPE in the vicinity of the water interface were probed by neutron reflectivity (NR) measurement. Even in the presence of the α-methyl group on the main chain, PMPE slightly swelled near the water interface. The obtained results will give us an insight into a better design and construction of the polymers for several bioapplications..
76. Keiji Tanaka, Ken Kojio, The 45th summer seminar - For realization of sustainable society by time- and space-domain controls of fibers, Sen'i Gakkaishi, 71, 6, P267, 2015.
77. Hisao Matsuno, Toshiyuki Ohta, Atsuomi Shundo, Yasuo Fukunaga, Keiji Tanaka, Simple Surface Treatment of Cell-Culture Scaffolds with Ultrafine Bubble Water, LANGMUIR, 10.1021/la5035883, 30, 50, 15238-15243, 2014.12.
78. Tomoyasu Hirai, Shota Osumi, Hiroki Ogawa, Teruaki Hayakawa, Atsushi Takahara, Keiji Tanaka, Precise Synthesis and Surface Wettability of a Polymer with Liquid Crystalline Side Chains, MACROMOLECULES, 10.1021/ma5010265, 47, 15, 4901-4907, 2014.08.
79. Atsuomi Shundo, Yuuki Hoshino, Takahiro Higuchi, Yuji Matsumoto, PENALOZA DAVID JR PENULIAR, Keigo Matsumoto, Masahi Ohno, Katsuaki Miyaji, Masahiro Goto, Keiji Tanaka, Facile Microcapsule Fabrication by Spray Deposition of a Supramolecular Hydrogel
, RSC Advances
, 4, 68, 36097-36100, 2014.08.
80. Motonori Watanabe, Hidehisa Hagiwara, Aoi Iribe, Yudai Ogata, Kenta Shiomi, Aleksandar Staykov, Shintaro Ida, Keiji Tanaka, Tatsumi Ishihara, Spacer Effects in Metal-free Organic Dyes for Visible-light-driven Dye-sensitized Photocatalytic Hydrogen Production, JOURNAL OF MATERIALS CHEMISTRY A, 10.1039/c4ta02720e, 2, 32, 12952-12961, 2014.08.
81. Ayanobu Horinouchi, Norifumi L. Yamada, Keiji Tanaka, Aggregation States of Polystyrene at Nonsolvent Interfaces, LANGMUIR, 10.1021/la500829p, 30, 22, 6565-6570, 2014.06.
82. Takaaki Date, Yuko Ueda, Hironori Atarashi, Toshiki Sawada, Hideyo Matsuzawa, Keiji Tanaka, Takeshi Serizawa, Difference in protein adsorption onto polymer films with or without thermal annealing, Journal of Nanoscience and Nanotechnology, 10.1166/jnn.2014.8580, 14, 4, 3106-3111, 2014.04, [URL], Protein adsorptions onto non-annealed (NA) and thermally annealed (TA) polyetherimide films were examined by surface plasmon resonance measurements. Proteins adsorbed onto the NA films with smaller adsorption constants in comparison with the TA films. Neutron reflectivity measurements of the two films suggested that the outermost region of the NA films swelled with larger amounts of water molecules than the TA films. It is plausible that the aforementioned difference in the protein adsorption properties is derived from the difference in the interfacial aggregation structures of the two films..
83. Jie Zhan, Hisao Matsuno, Hiroyasu Masunaga, Ogawa Hiroki, Keiji Tanaka, Green Solid Films with Tunable Mechanical Properties Made from Deoxyribonucleic Acid, NPG ASIA MATERIALS, 10.1038/am.2014.4, 6, e92, 2014.03.
84. Yukari Oda, Ayanobu Horinouchi, Daisuke Kawaguchi, Hisao Matsuno, Shokyoku Kanaoka, Sadahito Aoshima, Keiji Tanaka, Effect of Side-Chain Carbonyl Groups on the Interface of Vinyl Polymers with Water, Langmuir, 10.1021/la404802j, 30, 5, 1215-1219, 2014.02.
85. Yukari Oda, Keiji Tanaka, Aggregation states and molecular motion of well-defined vinyl polymers at the water interface, KOBUNSHI RONBUNSHU, 10.1295/koron.71.343, 71, 8, 343-351, 2014.01, [URL], We investigated the conformation of PMMA in thin films at the air-water interface by sum frequency generation (SFG) spectroscopy and discuss the effect of stereoregularity on the interfacial structure of PMMA. At the air interface, isotactic PMMA takes a helical conformation where the hydrophilic carbonyl groups are oriented towards the interfacial region of the film. Thus, even though the polymer chains come in contact with water, the chain conformation at the interface changes very little. The structure of syndiotactic PMMA at the air and water interfaces is significantly different. Poly(methyl 2-propenyl ether) (PMPE), synthesized via living cationic polymerization, is structurally similar to PMMA, but it lacks the carbonyl group. We discuss the effect of the carbonyl group on the water structure at the interface by comparing the results of our measurements to the previously reported PMMA-water system. This knowledge is crucial for the design and construction of highly-functionalized polymer interfaces for biological applications..
86. Atsuomi Shundo, Yuuki Hoshino, Takahiro Higuchi, Yuji Matsumoto, David P. Penaloza, Keigo Matsumoto, Masashi Ohno, Katsuaki Miyaji, Masahiro Goto, Keiji Tanaka, Facile microcapsule fabrication by spray deposition of a supramolecular hydrogel, RSC Advances, 10.1039/c4ra04636f, 4, 68, 36097-36100, 2014.01, [URL], A peptide amphiphile dispersed in water induces the formation of a supramolecular hydrogel. By spraying this hydrogel onto a solid surface, its hierarchical fibril structure remained unchanged even after water evaporation. Interestingly, there were microcapsules on the substrate surface as a result of the process of spray-drying the hydrogel. This journal is.
87. Atsuomi Shundo, Keiji Tanaka, Mesoscopic heterogeneity in supramolecular network systems, Nihon Reoroji Gakkaishi, 10.1678/rheology.42.89, 42, 2, 89-95, 2014.01, [URL], Molecules are often assembled by themselves with a large aspect ratio, leading to the formation of network structure based on their entanglements. Such systems, so-called "supramolecular network systems" possess hierarchical structure with various length scales ranging from nanometer to micrometer. Thus, to give a better understanding of dynamics for the supramolecular network systems, it is necessary to examine the structure and physical properties at various length scales, and clarify the correlation. By using optical tweezers and particle tracking techniques, we here show the local rheological properties in a worm-like micelle solution and a supramolecular hydrogel, which are formed by the networks based on the self-assembly of the amphiphilic molecules in water. In these techniques, viscoelastic information can be accessed on the basis of the movement of probe particles dispersed in a sample to be measured. For the worm-like micelle solution, we found that the viscoelastic functions (G′ and G″ ) varied depending on the location measured and the location-dependent variation of G′ and G″ was observed only at the measurement timescale being shorter than the relaxation time. This can be understood by taking into account that there exists a concentration fluctuation in the solution. Such fluctuation can be regard as a spatial heterogeneity when one takes a snapshot of the solution at a time shorter than the relaxation time. Also, the heterogeneity in the rheological properties was observed in a sol obtained by physically disrupting the supramolecular hydrogel. The extent of the heterogeneity decreased as a solto-gel transition proceeded. Such homogenization was associated with the change in the network structure rather than that in the molecular assembled state, which remains comparable in the sol and gel..
88. Yudai Ogata, Daisuke Kawaguchi, Norifumi L. Yamada, Keiji Tanaka, Multistep Thickening of Nafion Thin Films in Water, ACS Macro Letters, 10.1021/mz400322q, 2, 10, 856-859, 2013.10.
89. Atsuomi Shundo, Koichiro Hori, PENALOZA DAVID JR PENULIAR, Kazuki Yoshihiro, Annaka Masahiko, Keiji Tanaka, Nonsolvents-induced Swelling of Poly(methyl methacrylate) Nanoparticles
, Physical Chemistry Chemical Physics, 15, 39, 16574-16578, 2013.10.
90. Atsuomi Shundo, Koichiro Hori, David P. Penaloza, Kazuki Yoshihiro, Annaka Masahiko, Keiji Tanaka, Nonsolvents-induced swelling of poly(methyl methacrylate) nanoparticles, Physical Chemistry Chemical Physics, 10.1039/c3cp52673a, 15, 39, 16574-16578, 2013.10, [URL], Polymer nanoparticles have been used in a wide variety of applications. In most of these applications, they are generally dispersed in a non-solvent. However, the effect of the non-solvent on the structure, physical properties and function of the nanoparticles has not yet ever taken into account. In this study, monodispersed poly(methyl methacrylate) (PMMA) nanoparticles were prepared by a surfactant-free emulsion polymerization. The PMMA nanoparticles were dispersed in water and in methanol, both typical non-solvents for PMMA, so that we could discuss the effect of the non-solvent on the nanoparticles. Dynamic light scattering measurements revealed that the hydrodynamic radius of the PMMA nanoparticles in methanol was larger than the same PMMA dispersed in water. Their DLS values were also larger than the radius of the nanoparticles measured by atomic force microscopy. When pyrene was dispersed in methanol with the PMMA nanoparticles, it was incorporated into the nanoparticles. These results clearly indicate that non-solvent molecules can be sorbed into polymer nanoparticles because the area of the interface, where polymer segments might be dissolved into liquid phases, as the total volume is quite larger for such nanoparticles. Therefore, based on our findings, it can be arguably established that the present assumption for a polymer not to be swollen in its non-solvent is not necessarily true..
91. Shinichiro Shimomura, Hisao Matsuno, Keiji Tanaka, Effect of Mechanical Instability of Polymer Scaffolds on Cell Adhesion, Langmuir, 10.1021/la4027706, 29, 35, 11087-11092, 2013.09.
92. Atsuomi Shundo, Koichiro Hori, Takuya Ikeda, Nobuo Kimizuka, Keiji Tanaka, Design of a Dynamic Polymer Interface for Chiral Discrimination, Journal of the American Chemical Society, 10.1021/ja404701s, 135, 28, 10282-10285, 2013.07.
93. PENALOZA DAVID JR PENULIAR, Atsuomi Shundo, Keigo Matsumoto, Masashi Ohno, Katsuaki Miyaji, Masahiro Goto, Keiji Tanaka, Spatial Heterogeneity in the Sol-gel Transition of a Supramolecular System
, Soft Matter, 9, 21, 5166-5172, 2013.06.
94. Ayanobu Horinouchi, Keiji Tanaka, An Effect of Stereoregularity on the Structure of Poly(methyl methacrylate) at Air and Water Interfaces, RSC Advances, 3, 24, 9446-9452, 2013.06.
95. Ayanobu Horinouchi, Keiji Tanaka, An effect of stereoregularity on the structure of poly(methyl methacrylate) at air and water interfaces, RSC Advances, 10.1039/c3ra40631h, 3, 24, 9446-9452, 2013.06, [URL], We here show the interfacial conformation of isotactic poly(methyl methacrylate) (i-PMMA) in films as revealed by sum-frequency generation vibrational spectroscopy, which possesses the best depth resolution among available techniques, and discuss an effect of stereoregularity on the interfacial structure of PMMA. At the air interface, i-PMMA takes the trans-gauche backbone conformation with some degree of main chain distortion and/or of trans-trans conformation. This may lead to a helical conformation of i-PMMA chains where the hydrophilic carbonyl groups, as well as hydrophobic methylene, α-methyl, and ester methyl groups, are oriented towards the outermost region of the i-PMMA film. Thus, even though i-PMMA chains come in contact with water, the chain conformation at the interface was little changed. These structural details of i-PMMA at the air and the water interfaces are significantly different from those observed for s-PMMA..
96. David P. Penaloza, Atsuomi Shundo, Keigo Matsumoto, Masashi Ohno, Katsuaki Miyaji, Masahiro Goto, Keiji Tanaka, Spatial heterogeneity in the sol-gel transition of a supramolecular system, Soft Matter, 10.1039/c3sm50225b, 9, 21, 5166-5172, 2013.06, [URL], Heating and then cooling down a dispersion of a peptide amphiphile in water forms hierarchical fibril structures leading to a supramolecular hydrogel. When the gel was physically broken apart by shaking, it transformed into a sol state. After aging it at room temperature for a given time, it returned to the gel state (re-gelation). To obtain a better understanding of such re-gelation processes, we have applied particle tracking to the sol obtained by disrupting the gel, as a function of aging time. The sol was more heterogeneous at the micrometer scale than the initial gel in terms of its viscoelastic properties, and the extent of the heterogeneity in the sol decreased as the re-gelation proceeded. The origin of the heterogeneity could be directly associated with a fibril network confirmed from Fourier-transform infrared spectroscopic, small-angle X-ray scattering and fluorescence microscopic measurements. The particle tracking study using different particle sizes suggested that the characteristic length scale of the heterogeneous network was not larger than 3 μm. This knowledge might be useful for understanding and controlling the gelation, thereby leading to the design and functionalization of soft materials..
97. Tomoyasu Hirai, Masayuki Haraguchi, Atsushi Sakai, PENALOZA DAVID JR PENULIAR, Masaaki Ozawa, Katsuaki Miyaji, Keiji Tanaka, Water-sliding Property of Polyacrylates with Different Fluoro Side Chains, CHEMISTRY LETTERS, 10.1246/cl.130012, 42, 5, 483-485, 2013.05.
98. Hironori Atarashi, Keiji Tanaka, Tomoyasu Hirai, Koichiro Hori, Masahiro Hino, Hiroshi Morita, Takeshi Serizawa, Uptake of Water in As-spun Poly(methyl methacrylate) Thin Films, RSC Advances, 10.1039/c3ra23066j, 3, 11, 3516-3519, 2013.03.
99. Ayanobu Horinouchi, Yoshihisa Fujii, Keiji Tanaka, Interfacial dynamics of poly(methyl methacrylate) in water, 4th International Symposium on Slow Dynamics in Complex Systems: Keep Going Tohoku
4th International Symposium on Slow Dynamics in Complex Systems
Keep Going Tohoku
, 10.1063/1.4794616, 1518, 459-461, 2013.03, [URL], Aggregation states of polymers at the surface generally tend to alter to their most stable ones in response to their surrounding environment. We here apply a time-resolved contact angle measurement to examine the rate of the surface reorganization of poly(methyl methacrylate) (PMMA) in water. By doing these measurements at various temperatures, it is possible to extract the apparent activation energy of the surface dynamics based on the relation of the surface relaxation time and temperature. Also, sum-frequency generation spectroscopy revealed that the surface reorganization involves the conformational changes in the main chain portion as well as the side chains. Hence, the dynamics observed here might reflect the segmental motion at the outermost region of the PMMA film, in which water plays as a plasticizer..
100. Hirofumi Tsuruta, Yoshihisa Fujii, Masao Doi, Hiroshi Morita, Keiji Tanaka, Relaxation of polystyrene at interface with solid substrate, 4th International Symposium on Slow Dynamics in Complex Systems: Keep Going Tohoku
4th International Symposium on Slow Dynamics in Complex Systems
Keep Going Tohoku
, 10.1063/1.4794617, 462-465, 2013.03, [URL], The local conformation of polymer chains in a film at the interface with a substrate was studied by sumfrequency generation spectroscopy. When a polystyrene (PS) film was prepared on a quartz substrate by a spin-coating method, the chains were aligned in the interfacial plane of the substrate. This interfacial orientation of chains was not observed for a PS film prepared by a solvent-casting method. The local conformation of chains at the substrate interface was interestingly unchanged even at a temperature that was 80 K higher than the bulk glass transition temperature. This observation indicates that polymer chains at the substrate interface can be only partially relaxed under conditions where the bulk chains are fully relaxed. On the other hand, interfacial chains could be easily relaxed by the solvent annealing..
101. Masayuki Haraguchi, Tomoyasu Hirai, Masaaki Ozawa, Katsuaki Miyaji, Keiji Tanaka, "Hydrophobic Acrylic Hard Coating by Surface Segregation of Hyper-branched Polymers", APPLIED SURFACE SCIENCE, 10.1016/j.apsusc.2012.11.160, 266, 1, 235-238, 2013.02.
102. Atsuomi Shundo, PENALOZA DAVID JR PENULIAR, Keiji Tanaka, "Microscopic Heterogeneity in Viscoelastic Properties of Molecular Assembled Systems", CHINESE JOURNAL OF POLYMER SCIENCE, 10.1007/s10118-013-1193-z, 31, 1, 1-11, 2013.01.
103. Hirofumi Tsuruta, Yukari Ikinaga, Yoshihisa Fujii, Keiji Tanaka, "A Simple Approach for Surface Hardening of Polystyrene", Applied Surface Science, 10.1016/j.apsusc.2012.10.070, 264, 1, 589-592, 2013.01.
104. Atsuomi Shundo, Koichiro Hori, PENALOZA DAVID JR PENULIAR, Keiji Tanaka, "Optical Tweezers with Fluorescence Detection for Temperature-dependent Microrheological Measurements", REVIEW OF SCIENTIFIC INSTRUMENTS, 10.1063/1.4789429, 84, 1, 014103-1-014103-5, 2013.01.
105. Yoshihisa Fujii, Hiroshi Morita, Atsushi Takahara, Keiji Tanaka, Mobility gradient of polystyrene in films supported on solid substrates, Glass Transition, Dynamics and Heterogeneity of Polymer Thin Films, 10.1007/12_2012_175, 1-28, 2013.01, [URL], In this review, we show the distribution of glass transition temperature (T g) in monodisperse polystyrene (PS) films coated on silicon oxide layers along the direction normal to the surface. Scanning force microscopy with a lateral force mode revealed that surface T g () was lower than the corresponding bulk T g (). Interestingly, the glass transition dynamics at the surface was better expressed by an Arrhenius equation than by a Vogel-Fulcher-Tamman equation. Interdiffusion experiments for PS bilayers at various temperatures, above and below, enabled us to gain direct access to the mobility gradient in the surface region. T g at the solid substrate was examined by fluorescence lifetime measurements using evanescent wave excitation. The interfacial T g was higher than the corresponding. The extent of the elevation was a function of the distance from the substrate and the interfacial energy. The T g both at the surface and interface was also studied by the coarse-grained molecular dynamics simulation. The results were in good accordance with the experimental results. Finally, dynamic mechanical analysis for PS in thin and ultrathin films was made. The relaxation time for the segmental motion became broader towards the faster and slower sides, due probably to the surface and interfacial mobility. Graphical Abstract:.
106. Daisuke Kawaguchi, Keiji Tanaka, Structures and physical properties at surfaces and interfaces of polymers, Toraibarojisuto/Journal of Japanese Society of Tribologists, 58, 10, 742-749, 2013.
107. 菊地貴子、大武義人、仲山和海、堀雅文、田中敬二, "再生ポリカーボネートの判別手法の開発", 高分子論文集, 68, 11, 731-736, 2012.11.
108. Cui Zhang, Yoshihisa Fujii, Keiji Tanaka, "Effect of Long Range Interactions on the Glass Transition Temperature of Thin Polystyrene Films", ACS MACRO LETTERS, 10.1021/mz300391g, 1, 11, 1317-1320, 2012.11.
109. Tomoyasu Hirai, Kaoru Kawasaki, Keiji Tanaka, Interfacial kinetics of a model epoxy-amine addition reaction, Physical Chemistry Chemical Physics, 10.1039/c2cp42673k, 14, 39, 13532-13534, 2012.10, [URL], The kinetics of the addition reaction at a solid interface for a model epoxy-amine system composed of monofunctionalized phenyl glycidyl ether and hexylamine was examined. The chemical character for the reaction of this system at the interface was the same as that in the bulk, while the physical nature was significantly different. Slowing down of the diffusion for the reactants in close proximity to the solid interface was also addressed by interfacial selective spectroscopy..
110. Yoshihisa Fujii, Keiji Tanaka, Thermal molecular motion of poly(methyl methacrylate) at various interfaces, Nihon Reoroji Gakkaishi, 10.1678/rheology.40.143, 40, 3, 143-149, 2012.10, [URL], Thermal molecular motion of poly(methyl methacrylate) (PMMA) at various interfaces, gases and liquids, was discussed. The α a- and β-relaxation processes were clearly observed even at the air interface. Both relaxation temperatures at the air interface were lower than the corresponding ones in the bulk. In addition, the extent to which the peak temperature for the surface relaxation processes fell below that of the bulk strongly depended on the stereoregularity of the films. Then, thermal molecular motion of PMMA was analyzed at gaseous carbon dioxide (CO 2) interface. It was more enhanced than that at gaseous nitrogen interface because CO 2 molecules were sorbed in the interfacial region, which played as plasticizing agents. Finally, mechanical properties of PMMA were also studied at interfaces with liquids such as water, hexane and methanol. The modulus decreased closer to the outermost region of the film. The extent to which the modulus decreased in the interfacial region was consistent with the amount of liquid sorbed into the film. Therefore, it can be claimed that interfacial molecular motion of polymers can be regulated on the basis of the aggregation states..
111. Akihiro Matsubayashi, Kenji Fukunaga, Keiji Tanaka, "Metal Ions/ion Clusters Transport in Glassy Polymer Films: Construction of Multi-layered Polymer and Metal Composite Films", Journal of Materials Chemistry, 10.1039/c2jm31923c, 22, 31, 15578-15585, 2012.08.
112. Masayuki Haraguchi, Tomoyasu Hirai, Masahiro Ozawa, Misao Miyamoto, Keiji Tanaka, One-step synthesis of hyper-branched polymer with perfluoroalkyl segments, KGK Kautschuk Gummi Kunststoffe, 65, 7-8, 34-38, 2012.07, Initiator-fragment incorporation radical polymerization (IFIRP) of commercially available fluorinated monomers was performed in the presence of cross-linking agents, resulting in a hyperbranched polymer with perfluoroalkyl groups (F-HBP). In our one-step method, a F-HBP was successfully prepared without gelation within 1 h. The FHBP exhibited interesting properties based on both the hyperbranched architecture and the perfluoroalkyl groups, such as good solubility in common organic solvents, high thermal stability, and low surface free energy..
113. Ayanobu Horinouchi, Hironori Atarashi, Yoshihisa Fujii, Keiji Tanaka, "Dynamics of Water-Induced Surface Reorganization in Poly(methyl methacrylate) Films", MACROMOLECULES, 10.1021/ma3002559, 45, 11, 4638-4642, 2012.06.
114. Hirofumi Tsuruta, Yoshihisa Fujii, Naoki Kai, Hiroshi Kataoka, Takashi Ishizone, Masao Doi, Hiroshi Morita, Keiji Tanaka, "Local Conformation and Relaxation of Polystyrene at Substrate Interface", MACROMOLECULES, 10.1021/ma3007202, 45, 11, 4643-4649, 2012.06.
115. Koichiro Hori, David P. Penaloza, Atsuomi Shundo, Keiji Tanaka, "Time-dependent heterogeneity in viscoelastic properties of worm-like micelle solutions"
, Soft Matter, 10.1039/c2sm25549a, 8, 28, 7361-7364, 2012.05.
116. David P. Penaloza, Koichiro Hori, Atsuomi Shundo, Keiji Tanaka, Spatial heterogeneity in a lyotropic liquid crystal with hexagonal phase, Physical Chemistry Chemical Physics, 10.1039/c2cp40284j, 14, 15, 5247-5250, 2012.04, [URL], Non-ionic surfactant hexaethylene glycol, C 12E 6, in water self-assembles into various kinds of mesophases by varying the surfactant concentration. A spatial heterogeneity was discussed on the basis of the diffusion of probe particles dispersed in the C 12E 6-water solution. Interestingly, at 50 wt% C 12E 6 where the hexagonal structure was formed, two kinds of motion of probe particles were observed: some particles normally diffused while others were restricted, indicating the existence of a heterogeneity in the physical properties. Such heterogeneity can be explained in terms of heterogeneous structures composed of hexagonal domains with isotropic-like regions..
117. Hirofumi Tsuruta, Yoshihisa Fujii, Keiji Tanaka, One-pot surface modification of rubbery polymer films, Polymer Chemistry, 10.1039/c1py00488c, 3, 2, 319-321, 2012.02, [URL], A novel method to modify the surface of rubbery polymer films on the basis of the preferential segregation of inorganic materials fed into the system in tiny amounts is proposed. The surface so prepared had several prominent properties such as surface hardness, anti-oxidant properties, transparency, and so forth..
118. Tomoyasu Hirai, Kaoru Kawasaki, Keiji Tanaka, "Interfacial kinetics of a model epoxy-amine addition reaction", Phys. Chem. Chem. Phys., 14, 39, 13532-13534 , 2012.01, 本論文はエポキシ/アミンのモデル反応に基づき、固体界面近傍における反応動力学評価を行ったものである。活性化エネルギー、衝突頻度因子の算出から、反応の活性化エネルギーはバルク、界面で不変である一方、バルクの衝突頻度因子は界面近傍におけるそれと比較して6倍程度であった。このことから、固体界面の存在はエポキシ硬化反応の化学的な因子には影響を与えず、物理的因子に大きな影響を与えることを明らかにした。.
119. Atsuomi Shundo, Yohei Okada, Fuyuki Ito, and Keiji Tanaka, ”Fluorescence Behavior of Dyes in Thin Films of Various Polymers”, Macromolecules, 10.1021/ma201901x, 45, 1, 2011.12.
120. Keiji Tanaka, “One-pot Surface Modification of Rubbery Polymer Films”, Polym. Chem., 10.1039/C1PY00488C, 3, 2, 319-321 , 2011.12.
121. Koichiro Hori, Hisao Matsuno, Keiji Tanaka, Sorption kinetics of methanol in thin poly(methyl methacrylate) films studied by optical reflectivity, Soft Matter, 10.1039/c1sm06098h, 7, 21, 10319-10326, 2011.11, [URL], To study the thickness dependence of methanol diffusion into poly(methyl methacrylate) (PMMA) films, an experimental method based on optical reflectivity was proposed. The method can cover a thickness range from the micrometre down to the nanometre scale using a single set-up. Methanol molecules diffuse into PMMA following a Case II mechanism in which they induce segmental motion of the matrix polymer. We observed two diffusion modes, fast and slow, assignable respectively to the outermost layer and the remaining internal region including the substrate interface. When the film becomes thinner, the ratio of the interfacial area to the total volume increases. This results in slowing down of the methanol diffusion due to the contribution of the depressed segmental mobility at the substrate interface. Interestingly, the thickness of the mobility-enhanced layer at the outermost region of the film similarly decreased with decreasing total thickness owing to the effect of the substrate interface..
122. A. Matsubayashi, K. Fukunaga, T. Tsuji, K. Ataka, H. Ohsaki, K. Tanaka,, “Band-selective Mirror Characteristics of Polymer/Metal Multilayer Films”,, Chem. Lett., 10.1246/cl.2011.1138, 40, 10, 1138-1139, 2011.10.
123. K. Hori, H. Matsuno, K. Tanaka, “Sorption Kinetics of Methanol in Thin Poly(methyl methacrylate) Films Studied by Optical Reflectivity”, Soft Matter, 7 , 21, 10319-10326, 2011.09.
124. Hironori Atarashi, Yoshihisa Fujii, Dai Yamazaki, Masahiro Hino, Hiroshi Morita, Keiji Tanaka, Density distributions of poly (methyl methacrylate) thin films in non-solvents, Kobunshi Ronbunshu, 10.1295/koron.68.608, 68, 9, 608-615, 2011.09, [URL], Recently, polymeric materials nave oeen widely used in applications sucn as medical materiais, in tnese applications, the surrace comes into contact with a different phase. Thus, their interfaces should be studied, both their structures as well as their dynamics. The density profiles of a perdeuterated poly(methyl methacrylate) (dPMMA) film in water, hexane, methanol, ethanol, 1-propanol, and 1-butanol were examined along the direction normal to the interface by neutron reflectivity (NR). Although these liquids are typical non-solvents for dPMMA, the liquid/polymer interfaces were diffuse in comparison with the air/polymer interface probably due to the partial dissolution of polymer segments at the outermost region of the film. Interestingly, in water, an anomalous swollen layer was formed beneath the diffused interface. On the other hand, such a swollen layer was not observed for the dPMMA films in alcohols. This is simply because alcohol molecules deeply penetrated into the films. The amounts of the alcohols penetrated are related to the interaction parameter. The fractional amount of nonsolvents at the substrate interface was higher than that in the internal region of the film..
125. Atsuomi Shundo, Keiko Mizuguchi, Misao Miyamoto, Masahiro Goto, Keiji Tanaka, “Controllable Heterogeneity in a Supramolecular Hydrogel”, Chem. Commun., 10.1039/c1cc12733k, 47, 31, 8844-8846, 2011.06.
126. Satoshi Miwa, Takako Kikuchi, Yoshito Ohtake, Keiji Tanaka, “Surface Degradation of Poly(ethylene-co-propylene-co-5-ethylidene-2-norbornene) Terpolymer by Ozone in Water”, Polym. Degrad. Stab., 10.1016/j.polymdegradstab.2011.05.001, 96, 8, 1503-1507, 2011.05.
127. T. Hirata, H. Matsuno, M. Tanaka, K. Tanaka, "Surface Segregation of Poly(2-methoxyethyl acrylate) in a Mixture with Poly(methyl methacrylate)”, Phys. Chem. Chem. Phys, 10.1246/cl.2011.366, 40, 4, 366-367, 2011.04.
128. Keiji Tanaka, Yoshihisa Fujii, Polymer structure and physical properties at non-solvent interfaces, Kobunshi, 60, 3, 148-152, 2011.03, Interfaces of polymers with "non-solvents" play an important role in their functional properties such as wettability, friction with lubricants, cell adhesion, and biocompatibility. To design and construct highly functionalized polymers for applications that exploit these characteristics, aggregation states of the polymers at the liquid interfaces must be understood as the first benchmark. However, this is experimentally difficult because such interfaces are buried. In this review, we introduce recent development of the issue with the advent of modem experimental techniques..
129. Toyoaki Hirata, Hisao Matsuno, Masaru Tanaka, Keiji Tanaka, Surface segregation of poly(2-methoxyethyl acrylate) in a mixture with poly(methyl methacrylate), Physical Chemistry Chemical Physics, 10.1039/c0cp02101f, 13, 11, 4928-4934, 2011.03, [URL], Poly(2-methoxyethyl acrylate) (PMEA) exhibits excellent blood compatibility. To understand why such a surface functionality exists, the surface of PMEA should be characterized in detail, structurally and dynamically, under not only ambient conditions, but also in water. However, a thin film of PMEA supported on a solid substrate can be easily broken, namely it is dewetted. Our strategy to overcome this difficulty is to mix PMEA with poly(methyl methacrylate) (PMMA). Differential scanning calorimetry and cloud point measurements revealed that the PMEA/PMMA blend has a phase diagram with a lower critical solution temperature. The blend surface was also characterized by X-ray photoelectron spectroscopy in conjunction with microscopic observations. Although PMEA is preferentially segregated over PMMA at the blend surface due to its lower surface free energy, the extent of segregation in the as-prepared films was not sufficient to cover the surface. Annealing the blend film at an appropriate temperature, higher than the glass transition temperature and lower than the phase-separation temperature of the blend, enabled us to prepare a stable and flat surface that was perfectly covered with PMEA..
130. H. Matsuno, J.-i. Nakahara, K. Tanaka, “Dynamic Mechanical Properties of Solid Films of Deoxyribonucleic Acid”, Biomacromolecules, 12 , 1, 173-178, 2011.01.
131. Takako Kikuchi, Yoshito Ohtake, Kazumi Nakayama, Masayuki Hori, Keiji Tanaka, Development of a method to identify recycled polycarbonate, KOBUNSHI RONBUNSHU, 10.1295/koron.68.731, 68, 11, 731-736, 2011.01, [URL], To encourage the recycling of materials, the government provides subsidizes for manufacturers which use recycled materials to process final products. Unfortunately, this causes a camouflage of recycled-content products. Hence, a method to judge whether the material is truly made of previously used source needs to be established. In this study, we focus on recycled plastics, especially, polycarbonate (PC). Plastics are thermally and mechanically damaged during its molding process and practical use. This leads to faster degradation of recycled plastics than the corresponding pristine ones. We here propose how we can identify recycled PC taking into account the degradation kinetics..
132. Hisao Matsuno, Jun Ichi Nakahara, Keiji Tanaka, Dynamic mechanical properties of solid films of deoxyribonucleic acid, Biomacromolecules, 10.1021/bm1010933, 12, 1, 173-178, 2011.01, [URL], Solid films of deoxyribonucleic acid (DNA) from salmon testes were prepared by a solvent-casting method. The thermal molecular motion of the DNA film was examined by dynamic mechanical analysis (DMA). Four absorption peaks and one shoulder of the loss modulus were observed in the temperature domain from approximately 150 to 490 K. To assign these, thermal analysis employing thermogravimetry (TG) and differential thermal analysis (DTA) was used in conjunction with ultraviolet (UV)-visible and Fourier-transform infrared (FT-IR) spectroscopy. It seems most likely that, in order of increasing temperature, they are a BI→BII conformational transition, a relatively large-scale movement associated with water molecules, water evaporation, thermal denaturation of DNA, and a glass transition..
133. Naokazu Idota, Kenichi Nagase, Keiji Tanaka, Teruo Okano, Annaka Masahiko, Stereoregulation of thermoresponsive polymer brushes by surface-initiated living radical polymerization and the effect of tacticity on surface wettability, Langmuir, 10.1021/la1024229, 26, 23, 17781-17784, 2010.12, [URL], In this study, stereocontrolled poly(N-isopropylacrylamide) (PIPAAm) brushes were grafted from surfaces by atom transfer radical polymerization (ATRP) in the presence of a Lewis acid, and the effect of PIPAAm brush tacticity on the thermoresponsive wettabiliy was investigated. PIPAAm grafted by ATRP in the presence of Y(OTf)3 showed high isotacticity, while the control brush polymerized in the absence of Y(OTf)3 was clearly atactic. The isotacticity and molecular weight of PIPAAm brushes were controlled by polymerization conditions. The wettability of isotactic PIPAAm-grafted surfaces decreased slightly below 10°C, although the phase transition temperature of atactic surface was 30°C, and the bulk isotactic polymer was water-insoluble between 5 and 45°C..
134. N. Idota, K. Nagase, K. Tanaka, T. Okano, M. Annaka, “Stereoregulation of Thermoresponsive Polymer Brushes by Surface-initiated Living Radical Polymerization and the Effect of Tacticity on Surface Wettability”, Langmuir, 26, 13 , 17781-17784, 2010.11.
135. Ifu Narayama, Daisuke Baba, Atsushi Takahara, Keiji Tanaka, Direct observation of surface and internal phase-separated structure of the active layer buried in organic photovoltaic cells, Applied Surface Science, 10.1016/j.apsusc.2010.07.093, 257, 3, 1145-1148, 2010.11, [URL], A phase-separated structure of the active layer, of variable thickness, buried in organic thin film solar cells (OTSC) was directly observed by scanning force microscopy (SFM) with the aid of a surface and interface cutting analysis system (SAICAS). This deals with SFM observation to both the surface and the internal regions of the OTSCs, leading to discussion about the formation of the overlayer in the active layer..
136. 三輪怜史、菊地貴子、大武義人、田中敬二, “オゾン水中におけるエチレン‐プロピレン‐ジエン三元共重合体の劣化機構”, 日本ゴム協会誌 , 83, 10, 324-330, 2010.10.
137. I. Narayama, D. Baba, A. Takahara, K. Tanaka, “Direct Observation of Surface and Internal Phase-separated Structure of the Active Layer Buried in Organic Photovoltaic Cells”, Appl. Surface Sci, 257, 1145-1148, 2010.09.
138. A. Horinouchi, Y. Fujii, N. L. Yamada, K. Tanaka, “Surface Reorganization of Thin Poly(methyl methacrylate) Films Induced by Water”, Chem. Lett., 39, 8, 810-811, 2010.08.
139. Ayanobu Horinouchi, Yoshihisa Fujii, Norifumi L. Yamada, Keiji Tanaka, Surface reorganization of thin poly(methyl methacrylate) films induced by water, Chemistry Letters, 10.1246/cl.2010.810, 39, 8, 810-811, 2010.07, [URL], Neutron reflectivity revealed that the surface aggregation states of poly(methyl methacrylate) film can be altered by water, which is a typical nonsolvent, in a relatively large scale..
140. Yohei Tateishi, Naoki Kai, Hidenori Noguchi, Kohei Uosaki, Toshihiko Nagamura, Keiji Tanaka, Local conformation of poly(methyl methacrylate) at nitrogen and water interfaces, Polymer Chemistry, 10.1039/b9py00227h, 1, 3, 303-311, 2010.05, [URL], The local conformation of poly(methyl methacrylate) (PMMA) chains at the nitrogen (N2) and water interfaces was studied by infrared-visible sum-frequency generation (SFG) spectroscopy. Although SFG spectra in the C-H region for PMMA at the N2 interface have been hitherto reported, the peak assignments are not in accord with one another. Thus, we first made accurate assignments of SFG peaks using films, which had been well annealed at a temperature above the glass transition temperature for a long time, of three different deuterated PMMAs as well as normal protonated PMMA. At the N 2 interface, hydrophobic functional groups such as α methyl, ester methyl and methylene groups were present. While the α methyl group was oriented along the direction parallel to the interface, ester methyl and methylene groups were oriented normal to the interface. Quantitative discussion concerning the orientation of the functional groups of PMMA at the N2 interface was aided by a model calculation. Once the PMMA film contacted water, the carbonyl groups of the PMMA side chains were oriented to the water phase to form hydrogen bonds with water molecules, resulting in the migration of ester methyl into the internal region of the film. Concurrently, the methylene groups became randomly oriented at the water interface and/or in part migrated into the internal region. Interestingly, the α methyl groups still existed at the water interface oriented along the parallel direction. The outermost region of PMMA in water can consist of hydrophilic and hydrophobic domains with sub-nanometre scale. Water molecules H-bond to themselves near the hydrophobic domains, leading to the formation of an ice-like structure of water molecules. However, water molecules adjacent to the hydrophilic domains H-bond with carbonyl groups..
141. Y. Tateishi, N. Kai, H. Noguchi, K. Uosaki, T. Nagamura, K. Tanaka, “Local Conformation of Poly(methyl methacrylate) at Nitrogen and Water Interfaces”, Polym. Chem., 1, 3, 303-311, 2010.04.
142. Y. Fujii, T. Nagamura, K. Tanaka, Relaxation Behavior of Poly(methyl Methacrylate) at a Water Interface, J. Phys. Chem. B. , 114, 10, 3457-3460 , 2010.03.
143. Yoshihisa Fujii, Toshihiko Nagamura, Keiji Tanaka, Relaxation behavior of poly(methyl methacrylate) at a water interface, Journal of Physical Chemistry B, 10.1021/jp909373g, 114, 10, 3457-3460, 2010.03, [URL], The relaxation behavior of poly(methyl methacrylate) (PMMA), spin-coated on a silicon wafer, at the water interface was examined by lateral force microscopy as a function of temperature and scanning rate. Even in water, the lateral force peak which was assigned to the segmental motion of PMMA plasticized by water molecules was clearly observed in the temperature domain. The apparent activation energy for the plasticized αa- relaxation process was much smaller than those for the original αa-relaxation processes at the intact surface and in the bulk. The depth profile of the glass transition temperature (Tg) of the PMMA film in water was obtained, showing that Tg decreases with proximity to the water phase. The Tg depression observed here was best explained in terms of the water content of the film, rather than a confinement effect..
144. Hironori Atarashi, Hiroshi Morita, Dai Yamazaki, Masahiro Hino, Toshihiko Nagamura, Keiji Tanaka, Swelling structure of thin poly(methyl methacrylate) films in various alkyl length alcohols, Journal of Physical Chemistry Letters, 10.1021/jz100041h, 1, 5, 881-885, 2010.03, [URL], Thin films of a typical glassy polymer in alcohol nonsolvents were structurally characterized by specular neutron reflectivity (NR) and were found to be discernibly swollen. The extent of penetration by the nonsolvent was determined by the chain length of the alcohol. Treating this situation as one of a macroscopic phase separation, the interaction Χ parameters for the polymer and nonsolvents combinations were extracted. This observation leads us to investigate the factors that control the nonsolvent/polymer interface, being an unusual example of a liquid/liquid interface. The fractional amount of nonsolvents at the substrate interface was higher than that in the internal region of the film. This segregation of a component in a phase-separated domain was explained in terms of an entropic factor..
145. H. Atarashi, H. Morita, D. Yamazaki, M. Hino, T. Nagamura, K. Tanaka, Swelling Structure of Thin Poly(methyl methacrylate) Films in Various Alkyl Length Alcohols, J. Phys. Chem. Lett. , 1, 5, 881-885 , 2010.02.
146. 道下浩征、赤堀敬一、田中敬二、松本広重、春田大蔵、永田吉憲、山本壽昭,石原達己, ナフィオン膜の電解条件下での安定性に及ぼす圧力の影響, Electrochemistry, 78, 1, 42-49 , 2010.01.
147. Hiroyuki Michishita, Kei Ichi Akabori, Keiji Tanaka, Hiroshi Matsumoto, Daizou Haruta, Yoshinori Nagata, Nagaaki Yamamoto, Tatsumi Ishihara, Effects of pressure on stability of nafion membrane under water electrolysis, Electrochemistry, 10.5796/electrochemistry.78.42, 78, 1, 42-49, 2010.01, [URL], In previous study, proton conductivity increased with increasing pressure under water electrolysis, so the effects of pressure on the stability of Nafion 117 have been studied. It was found that conductivity of Nafion 117 drastically decreased at initial few h and then gradually decreased in the following period under electrolysis condition. Decrease in conductivity can be explained by decomposition of Nafion 117. Decomposition of Nafion 117 is accelerated by increasing pressure. Solid state NMR, IR, and Raman spectroscopy suggested that the electrochemical oxidation of sulfo group was occurred at initial period followed by decomposition of CFn main or side chain. Therefore, initial increase in resistance can be explained by desorption of sulfo group in Nafion 117. Desorption of sulfo group also forms pin hole in Nafion membrane which may cause gas leakage under water electrolysis. Mechanical strength of Nafion membrane is also drastically decreased at initial electrolysis period. Consequently, chemical stability of Nafion 117 may cause serious problem for water electrolysis application and this study reveals that increasing pressure strongly accelerates the decomposition of Nafion 117..
148. Yoshihisa Fujii, Zhaohui Yang, Jessica Leach, Hironori Atarashi, Keiji Tanaka, Ophelia K.C. Tsui, Affinity of polystyrene films to hydrogen-passivated silicon and its relevance to the Tg of the films, Macromolecules, 10.1021/ma901851w, 42, 19, 7418-7422, 2009.10, [URL], Qualitatively different thickness dependences have been observed in the glass transition temperature, Tg, of polystyrene (PS) films supported by hydrogen-passivated silicon (H-Si). It has been suggested that upon annealing at high temperatures in air, the polymer/substrate interface of these films (i.e., PS/Si), though buried underneath the PS layer, might be oxidized, rendering the films a different polymer/substrate interface (i.e., PS/SiO x-Si), which may account for the different thickness dependences of the Tg observed. In this experiment, we examine if the buried substrate interface of PS/H-Si films can indeed be oxidized by annealing the films at 150 °C in air. Our result shows that a residual film does form on top of the H-Si surface, but it is a bound layer of PS. X-ray photoelectron spectroscopic (XPS) analyses and independence of the residual film on the initial PS thickness evidence that the H-Si substrate buried underneath a PS film is not oxidized by annealing. We discuss a possible explanation to how the different thickness dependences may be observed in the Tg of these films..
149. K. Akabori, H. Atarashi, M. Ozawa, T. Kondo, T. Nagamura, K. Tanaka, Glass Transition Behaviour of Hyper-branched Polymers, Polymer, 50, 20, 4868-4875, 2009.09.
150. Y. Fujii, H. Atarashi, M. Hino, T. Nagamura, K. Tanaka, Interfacial Width in Polymer Bilayer Films Prepared by Double Spin-coating and Floating Methods, ACS Appl. Mater. Interfaces, 1, 9, 1856-1859, 2009.09.
151. Y. Fujii, Z. Yang, J. Leach, H. Atarashi, K. Tanaka, O. K. C. Tsui, Affinity of Polystyrene Films to Hydrogen-Passivated Silicon and its Relevance to the Tg of the Films, Macromolecules , 42, 19, 7418-7422, 2009.09.
152. I. Narayama, K. Akabori, H. Morita, T. Nagamura, K. Tanaka, Nanoscopic Adhesion Test for Polymers by A Light-lever System, J. Phys. Conf. Ser. , 184, 012032 , 2009.09.
153. Kei ichi Akabori, Hironori Atarashi, Masaaki Ozawa, Tetsuo Kondo, Toshihiko Nagamura, Keiji Tanaka, Glass transition behavior of hyper-branched polystyrenes, polymer, 10.1016/j.polymer.2009.08.029, 50, 20, 4868-4875, 2009.09, [URL], Hyper-branched polystyrenes (HBPS) were synthesized. The bulk glass transition temperature (Tg) measured by differential scanning calorimetry (DSC) for two kinds of HBPS with an equivalent Mw, which were fractionated from different lots, were different, being respectively higher and lower than that of the corresponding linear polystyrene (PS). Infrared spectroscopy revealed that the Tg of HBPS increased with an increasing extent of intramolecular cross-linking, or cyclization, in the molecule. The segmental dynamics of HBPS was examined by dynamic mechanical analysis. The relaxation temperature for the segmental motion in HBPS was consistent with the DSC results. The fragility index was always lower for HBPS than for the linear PS, regardless of its primary structure and chain end chemistry. This would indicate that the segmental motion for HBPS is less cooperative than that of the linear PS, probably due to a lack of intermolecular chain entanglements in HBPS..
154. Yoshihisa Fujii, Hironori Atarashi, Masahiro Hino, Toshihiko Nagamura, Keiji Tanaka, Interfacial width in polymer bilayer films prepared by double-spin-coating and flotation methods, ACS Applied Materials and Interfaces, 10.1021/am9004336, 1, 9, 1856-1859, 2009.09, [URL], A spin-coating method with the aid of selective solvents has been used to construct multilayer structures for organic devices under the assumption that the solvents do not invade a preformed structure. To confirm the assumption, we examined the interfacial width (?i) of model polymer bilayers, composed of polystyrene and perdeuterated poly(methyl methacrylate), prepared by spin-coating and flotation methods. Neutron reflectivity measurements revealed that the ?i value was larger for the spin-coating method than for the flotation method. These results cast doubt on the validity of the assumption. This knowledge should be kept in mind when this method is applied to construct multilayer structures..
155. Takaaki Date, Mizuki Ishikawa, Koichiro Hori, Keiji Tanaka, Toshihiko Nagamura, Makio Iwahashi, Takeshi Serizawa, Water droplets for the symmetric adhesion of two poly(methyl methacrylate) films, Chemistry Letters, 10.1246/cl.2009.660, 38, 7, 660-661, 2009.07, [URL], Poly(methyl methacrylate) films were prepared by annealing below their glass-transition temperatures after spin-casting and were symmetrically pressed against each other with constant pressure in air. The films successfully adhered together with only water droplets. The interfacial adhesion strength was quantitatively examined by lap-shear tests. Polymer chains swollen with water molecules caused significant entanglement and resulted in strong adhesions..
156. T. Date, M. Ishikawa, K. Hori, K. Tanaka, T. Nagamura, M. Iwahashi and T. Serizawa, Water Droplets for the Symmetric Adhesion of Two Poly(methyl
methacrylate) Films, Chem. Lett., 38, 7, 660-661, 2009.05.
157. K. Tanaka, Y. Tateishi, Y. Okada, T. Nagamura, M. Doi, H. Morita, Interfacial Mobility of Polymers on Inorganic Solids
, J. Phys. Chem. B. , 113, 14, 4571-4577, 2009.04.
158. Keiji Tanaka, Yohei Tateishi, Yohei Okada, Toshihiko Nagamura, Masao Doi, Hiroshi Morita, Interfacial mobility of polymers on inorganic solids, Journal of Physical Chemistry B, 10.1021/jp810370f, 113, 14, 4571-4577, 2009.04, [URL], The segmental mobility of a typical amorphous polymer, polystyrene, at the interfaces with solid substrates was noninvasively examined by fluorescence lifetime measurements using evanescent wave excitation in conjunction with coarse-grained molecular dynamics simulation. The glass transition temperature (Tg) was discernibly higher at the interface than in the internal bulk region. Measurements at different incident angles of excitation pulses revealed that Tg became higher closer to the interface. The gradient became more marked with an increasing difference in the free energy at the interface between the polymer and solid substrate. The Tg value at the interface decreased with decreasing molecular weight. However, the decrement for the interfacial Tg was not as much as that for the bulk Tg, due to the restriction of chain end portions by the substrate. Finally, it was observed that when a film became thinner than 50 nm, the depressed mobility at the interface coupled with the enhanced mobility induced by the presence of the surface. The experimental and simulation results were in good accord with each other..
159. Atsushi Takahara, Keiji Tanaka, IUMRS-ICA 2008 symposium, sessions X. applications of synchrotron radiation and neutron beam to soft matter science and Y. frontier of polymeric nano-soft-materials - Precision polymer synthesis, self-assembling and their functionalization, Journal of Physics: Conference Series, 10.1088/1742-6596/184/1/011001, 184, 2009.01, [URL], Applications of Synchrotron Radiation and Neutron Beam to Soft Matter Science (Symposium X of IUMRS-ICA2008) Toshiji Kanaya, Kohji Tashiro, Kazuo Sakura Keiji Tanaka, Sono Sasaki, Naoya Torikai, Moonhor Ree, Kookheon Char, Charles C Han, Atsushi Takahara This volume contains peer-reviewed invited and contributed papers that were presented in Symposium X Applications of Synchrotron Radiation and Neutron Beam to Soft Matter Science at the IUMRS International Conference in Asia 2008 (IUMRS-ICA 2008), which was held on 9-13 December 2008, at Nagoya Congress Center, Nagoya, Japan. Structure analyses of soft materials based on synchrotron radiation (SR) and neutron beam have been developed steadily. Small-angle scattering and wide-angle diffraction techniques clarified the higher-order structure as well as time dependence of structure development such as crystallization and microphase-separation. On the other hand, reflectivity, grazing-incidence scattering and diffraction techniques revealed the surface and interface structural features of soft materials. From the viewpoint of strong interests on the development of SR and neutron beam techniques for soft materials, the objective of this symposium is to provide an interdisciplinary forum for the discussion of recent advances in research, development, and applications of SR and neutron beams to soft matter science. In this symposium, 21 oral papers containing 16 invited papers and 14 poster papers from China, India, Korea, Taiwan, and Japan were presented during the three-day symposium. As a result of the review of poster and oral presentations of young scientists by symposium chairs, Dr Kummetha Raghunatha Reddy (Toyota Technological Institute) received the IUMRS-ICA 2008 Young Researcher Award. We are grateful to all invited speakers and many participants for valuable contributions and active discussions. Organizing committee of Symposium (IUMRS-ICA 2008) Professor Toshiji Kanaya (Kyoto University) Professor Kohji Tashiro (Toyota Technological Institute) Professor Kazuo Sakurai(Kitakyushu University) Professor Keiji Tanaka (Kyushu University) Dr Sono Sasaki (JASRI/Spring-8) Professor Naoya Torikai (KENS) Professor Moonhor Ree (POSTECH) Professor Kookheon Char (Seoul National University) Professor Charles C Han (CAS) Professor Atsushi Takahara(Kyushu University) Frontier of Polymeric Nano-Soft-Materials, Precision Polymer Synthesis, Self-assembling and Their Functionalization (Symposium Y of IUMRS-ICA2008) Seiichi Kawahara, Rong-Ming Ho, Hiroshi Jinnai, Masami Kamigaito, Takashi Miyata, Hiroshi Morita, Hideyuki Otsuka, Daewon Sohn, Keiji Tanaka It is our great pleasure and honor to publish peer-reviewed papers, presented in Symposium Y Frontier of Polymeric Nano-Soft-Materials Precision Polymer Synthesis, Self-assembling and Their Functionalization at the International Union of Materials Research Societies International Conference in Asia 2008 (IUMRS-ICA2008), which was held on 9-13 December 2008, at Nagoya Congress Center, Nagoya, Japan. Polymeric nano-soft-materials are novel outcomes based on a recent innovative evolution in polymer science, i.e. precision polymer synthesis, self-assembling and functionalization of multi-component systems. The materials are expected to exhibit specific functions and unique properties due to their hierarchic morphologies brought either by naturally-generated ordering or by artificial manipulation of the systems, e.g., crystallization and phase-separation. The emerging precision synthesis has brought out new types of polymers with well-controlled primary structures. Furthermore, the surface and interface of the material are recognized to play an important role in the outstanding mechanical, electrical and optical properties, which are required for medical and engineering applications. In order to understand structure-property relationships in the nano-soft-materials, it is indispensable to develop novel characterization techniques. Symposium Y aimed to provide recent advances in polymer synthesis, self-assembling processes and morphologies, and functionalization of nano-soft-materials in order to initiate mutual and collaborative research interest that is essential to develop revolutionarily new nano-soft-materials in the decades ahead. Four Keynote lectures, 15 invited talks and 30 posters presented important new discoveries in polymeric nano-soft-materials, precision polymer synthesis, self-assembling and their functionalization. As for the precision polymer synthesis, the latest results were provided for studies on synthesis of polyrotaxane with movable graft chains, organic-inorganic hybridization of polymers, supra-molecular coordination assembly of conjugated polymers, precision polymerization of adamantane-containing monomers, production of high density polymer brush and synthesis of rod coil type polymer. The state-of-the-art results were introduced for the formation of nano-helical-structure of block copolymer containing asymmetric carbon atoms, self-assembling of block copolymers under the electric field, self-assembling of liquid crystalline elastomers, preparation of nano cylinder template films and mesoscopic simulation of phase transition of polymers and so forth. Moreover, recent advantages of three-dimensional electron microtomography and scanning force microscopy were proposed for analyses of nano-structures and properties of polymeric multi-component systems. Syntheses, properties and functions of slide-ring-gel, organic-inorganic hybrid hydrogels, hydrogel nano-particles, liquid-crystalline gels, the self-oscillating gels, and double network gels attracted participants' attention. Modifications of naturally occurring polymeric materials with supercritical carbon dioxide were introduced as a novel technology. Some of the attractive topics are presented in this issue. We are grateful to all the speakers and participants for valuable contributions and active discussions. Organizing committee of Symposium Y (IUMRS-ICA 2008) Chair Seiichi Kawahara (Nagaoka University of Technology, Japan) Vice Chairs Rong-Ming Ho (National Tsing Hua University, Taiwan) Hiroshi Jinnai (Kyoto Institute of Technology, Japan) Masami Kamigaito (Nagoya University, Japan) Takashi Miyata (Kansai University, Japan) Hiroshi Morita (National Institute of Advanced Industrial Science and Technology, Japan) Hideyuki Otsuka (Kyushu University, Japan) Daewon Sohn (Hanyang University, Korea) Keiji Tanaka (Kyushu University, Japan).
160. Ifu Narayama, Keiichi Akabori, Hiroshi Morita, Toshihiko Nagamura, Keiji Tanaka, Nanoscopic adhesion test for polymers by a light-lever system, Journal of Physics: Conference Series, 10.1088/1742-6596/184/1/012032, 184, 2009.01, [URL], Polymer nano-adhesion between a cantilever tip coated with polymer and a flat polymer film was studied by a light-lever system using an atomic force microscope. The polymer interface was adhered at a temperature above the surface glass transition temperature for a given time. Nano-adhesion force (F nano), at which the tip was detached from the surface, was estimated from the deflection of the lever with a known spring constant. Nano-adhesion strength (GN) was simply obtained dividing Fnano by the contact area, which was estimated on the basis of Johnson-Kendall-Roberts theory. The time evolution of the interfacial thickness was independently examined by dynamic secondary ion mass spectrometry. Interestingly, G N increased with increasing interfacial thickness. However, it can be hardly judged whether GN is proportional to the interfacial thickness with the exponent of 1 or 2. Then, temperature dependence of G N was examined. Above the bulk glass transition temperature, the relation between temperature and GN was well expressed by a Williams-Landel-Ferry type equation. This means that the nano-adhesion strength is governed by friction between segments. Once this is accepted, GN should be proportional to the interfacial thickness with the exponent of 2..
161. Fumi Ariura, Keiji Tanaka, Toshihiko Nagamura, Michel Schappacher, Redouane Borsali, Alain Deffieux, Investigations of bulk properties of comb polystyrene, 235th ACS National Meeting, Spring 2008
American Chemical Society, Polymer Preprints, Division of Polymer Chemistry
, 49, 1, 52-53, 2008.09.
162. T. Date, K. Tanaka, T. Nagamura, T Serizawa, Directional Affinity of Short Peptides for Synthetic Polymers
, Chem. Mater. , 20(14), 4536-4538 , 2008.07.
163. Takaaki Date, Keiji Tanaka, Toshihiko Nagamura, Takeshi Serizawa, Directional affinity of short peptides for synthetic polymers, Chemistry of Materials, 10.1021/cm703603f, 20, 14, 4536-4538, 2008.07, [URL], A study was conducted to demonstrate the directional affinities of the c02 peptides with adhesion forces of the c02 peptide immobilized onto the atomic force microscopy (AFM) cantilever against PMMA surfaces. The study also demonstrated material-binding peptides with short sequences for interactions with artificial materials. The study developed a force-displacement curve by combining the cantilever tip coated with B-c02 and the target it-PMMA surface. The study proved that c02 peptide immobilized without denaturation during the force measurement. The study found that modification of the c02 peptide with foreign molecules can be used as a process for developing novel peptidyl nanomaterials. The study confirmed that short peptides show directional affinity for target artificial materials based on adhesion force and kinetic measurements..
164. Daisuke Kawaguchi, Atsushi Takano, Yushu Matsushita, Keiji Tanaka, Toshihiko Nagamura, Naoya Torikai, Interdiffusion of cyclic polystyrene whose molecular weight is larger than the critical entanglement molecular weight, Nihon Reoroji Gakkaishi, 10.1678/rheology.36.113, 36, 2, 113-115, 2008.07, [URL], Interdiffusion of cyclic polystyrene (c-hPS) / cyclic deuterated polystyrene (c-dPS) laminated film whose molecular weights are ca.50 k was examined by neutron reflectivity and dynamic secondary ion mass spectroscopy. It has been found that time evolution of the interfacial thicknesses of (c-hPS/c-dPS) multi-layer films are similar to those of the corresponding linear hPS/linear dPS (l-hPS/l-dPS) bilayer films at short time region. However, at the annealing time longer than 5×103 s, the interfacial thicknesses of (c-hPS/c-dPS) multi-layer films are evidently larger than those of the (l-hPS/l-dPS) films at each observing time. These results can be explained in terms of the less entanglement nature of cyclic polymers than that of the linear ones..
165. Kei Ichi Akabori, Keiji Tanaka, Hiroki Murase, Atsushi Takahara, Tisato Kajiyama, Model analysis of scanning viscoelasticity microscopy and its applications to polymer surfaces, Nihon Reoroji Gakkaishi, 10.1678/rheology.36.87, 36, 2, 87-92, 2008.07, [URL], Scanning viscoelasticity microscopy (SVM) with a mechanical model analysis was applied to polystyrene (PS) surfaces. When the surface was in a glassy state, that is, in an elastic regime, the SVM vibrational system can be simply expressed by a series model composed of two springs such as a cantilever and the sample surface. Once the surface reaches in a viscoelastic regime, a damping factor must be incorporated into the model surface. The spring constants for the PS surfaces being in glassy and transition states were successfully extracted by the analysis. The surface value even for the glassy state was lower than the corresponding bulk value by a few decades..
166. K. Tanaka, N. Sanada, M. Hikita, T. Nakamura, T. Kajiyama, A. Takahara, Surface Depth Analysis for Fluorinated Block Copolymer Films by X-ray Photoelectron Spectroscopy Using C60 Cluster Ion Beam, Appl. Surface Sci., 254(17), 5435-5438, 2008.06.
167. Keiji Tanaka, Noriaki Sanada, Masaya Hikita, Tetsuya Nakamura, Tisato Kajiyama, Atsushi Takahara, Surface depth analysis for fluorinated block copolymer films by X-ray photoelectron spectroscopy using C 60 cluster ion beam, Applied Surface Science, 10.1016/j.apsusc.2008.02.089, 254, 17, 5435-5438, 2008.06, [URL], X-ray photoelectron spectroscopy (XPS) using fullerene (C 60 ) cluster ion bombardment was applied to films of a fluorinated block copolymer. Spectra so obtained were essentially different from those using Ar ion beam. Structure in the surface region with the depth down to 60 nm drawn on the basis of XPS with C 60 beam was essentially the same as the one drawn by the result using dynamic secondary ion mass spectrometry, which is a well-established method for the depth analysis of polymers. This implies that XPS using C 60 beam enables one to gain access to the depth analysis of structure in polymer films with the depth range over the analytical depth of conventional XPS, that is, three times inelastic mean-free path of photoelectrons..
168. 赤堀敬一、田中敬二、村瀬浩貴、高原 淳、梶山千里, 走査粘弾性顕微鏡の力学モデル化と高分子表面への応用, レオロジー学会誌, 36(2), 87-92 , 2008.04.
169. 川口大輔、高野敦志、松下裕秀、田中敬二、長村利彦、鳥飼直也, 臨界絡み合い分子量を超える長さを有する環状ポリスチレンの積層膜界面における相互拡散, レオロジー学会誌, 36(2), 113-115, 2008.04.
170. H. Sugihara, K. Oya, H. Murase, K. Akabori, K. Tanaka, T. Kajiyama, A. Takahara, Simultaneous Imaging for Surface and Internal Structure of Polymer Blend Thin Films, Appl. Surf. Sci. , 254(10), 3180-3183, 2008.03.
171. Y. Fujii, H. Atarashi, T. Nagamura, K. Tanaka, Entanglement Effect on Film Retention of Poly(methyl methacrylate) in Methanol, Chem. Lett. , 37(3), 326-327, 2008.03.
172. Yoshihisa Fujii, Hironori Atarashi, Toshihiko Nagamura, Keiji Tanaka, Entanglement effect on film retention of poly(methyl methacrylate) in methanol, Chemistry Letters, 10.1246/cl.2008.326, 37, 3, 326-327, 2008.03, [URL], Morphology for films of poly(methyl methacrylate) with various molecular weights was observed before and after methanol immersion by using atomic force microscopy so that the effect of chain entanglement on film retention of a polymer in a liquid can be discussed..
173. Hideki Sugihara, Kazuyuki Oya, Hiroki Murase, Keiichi Akabori, Keiji Tanaka, Tisato Kajiyama, Atsushi Takahara, Simultaneous imaging for surface and internal structure of polymer blend thin films, Applied Surface Science, 10.1016/j.apsusc.2007.10.080, 254, 10, 3180-3183, 2008.03, [URL], A novel experimental technique for three-dimensional (3D) visualization of phase-separated structure of polymer blend thin film was proposed. Polystyrene/poly(methyl methacrylate) (PS/PMMA) blend thin films with the thickness of approximately 100 nm were cut at extremely low angle by utilizing surface and interface cutting analysis system (SAICAS), and the cross-section was exposed as gradient surface with the width of approximately 2.5 μm. SFM investigation for the grazing cross-section imaged the detailed internal and surface phase separated structure of the (PS/PMMA) blend thin films on one image..
174. K. Tanaka, Y. Fujii, H. Atarashi, M. Hino, T. Nagamura,, Non-solvents Cause Swelling at the Interface with Poly(methyl Methacrylate) Films, Langmuir , 24(1), 296-301 , 2008.01.
175. Keiji Tanaka, Yoshihisa Fujii, Hironori Atarashi, Kei Ichi Akabori, Masahiro Hino, Toshihiko Nagamura, Nonsolvents cause swelling at the interface with poly(methyl methacrylate) films, Langmuir, 10.1021/la702132t, 24, 1, 296-301, 2008.01, [URL], Density profiles of a perdeuterated poly(methyl methacrylate) (dPMMA) film spin-coated on a substrate in water, hexane, and methanol, which are "nonsolvents" for dPMMA, were examined along the direction normal to the interface by specular neutron reflectivity (NR). The interfaces of dPMMA with the liquids were diffuse in comparison with the pristine interface with air; the interfacial width with water was thicker than that with hexane. Interestingly, in water, the dPMMA film was composed of a swollen layer and the interior region, which also contained water, in addition to the diffused layer. The interface of dPMMA with hexane was sharper than that with water. Although there were slight indications of a swollen layer for the dPMMA in hexane, the solvent molecules did not penetrate significantly into the film. On the other hand, in methanol, the whole region of the dPMMA film was strikingly swollen. To conserve mass, the swelling of the film by the nonsolvents is accompanied by an increase in the film thickness. The change in the film thickness estimated by NR was in excellent accord with the results of direct observations using atomic force microscopy (AFM). The modulus of dPMMA in the vicinity of the interfaces with liquids was also examined on the basis of force-distance curves measured by AFM. The modulus decreased closer to the outermost region of the film. The extent to which the modulus decreased in the interfacial region was consistent with the amount of liquid sorbed into the film..
176. Keiji Tanaka, Toshiyuki Shikata, A special issue for rheology in surfaces, interfaces and thin films, Nihon Reoroji Gakkaishi, 36, 2, 2008.
177. Y. Fujii, H. Atarashi, N. Yamada, N. Torikai, T. Nagamura, K. Tanaka, Gas Sorption into Surface of Poly(methyl methacrylate) Films at Atmospheric Pressure, Polym. J., 39(12), 1290-1294, 2007.12.
178. Yoshihisa Fujii, Hironori Atarashi, Norifumi Yamada, Naoya Torikai, Toshihiko Nagamura, Keiji Tanaka, Gas sorption into surface of poly(methyl methacrylate) films at atmospheric Pressure, Polymer Journal, 10.1295/polymj.PJ2007070, 39, 12, 1290-1294, 2007.12, [URL], Interfacial structure of deuterated poly(methyl methacrylate) (dPMMA) and polystyrene (dPS) films with gases such as carbon dioxide (CO2) and nitrogen (Ni) under a pressure of 0.1 MPa was examined by neutron reflectivity (NR). The interface was analyzed using a model that the density of the outermost region of the films was lower than that of the interior region. The density profile was expressed by a single exponential equation with a decay length (ζ). The &zeta. values for the dPMMA films under CO2 and N2 were larger than that under vacuum at a given temperature, and the extent was more remarkable under CO2 than under N2. On the other hand, such a gas sorption was not clearly discerned for the dPS films. Finally, the surface relaxation in the dPMMA and dPS films under CO2 and N2 was discussed on the basis of lateral force measurements..
179. Yoshihisa Fujii, Kei Ichi Akabori, Keiji Tanaka, Toshihiko Nagamura, Chain conformation effects on molecular motions at the surface of poly(methyl methacrylate) films, Polymer Journal, 10.1295/polymj.PJ2006270, 39, 9, 928-934, 2007.11, [URL], Surface relaxation in syndiotactic (st-) and isotactic (it-) poly(methyl methacrylate) (PMMA) films was studied by lateral force microscopy. The αa- and β-relaxation processes were clearly observed even at the surface, permitting us to deduce the form of the dispersion map for the surface relaxation processes. Both relaxation temperatures at the surface were lower than the corresponding ones in the bulk. In addition, the extent to which the peak temperature for the surface relaxation processes fell below that of the bulk strongly depended on the stereoregularity of the films. The differences in the chain conformations between the surface and the bulk, which were more remarkable in the st-PMMA, produced this variation in surface mobility..
180. Y. Fujii, H. Atarashi, K. Akabori, M. Hino, K. Tanaka, T. Nagamura, Structural Analysis for A Poly(methyl methacrylate) Ultrathin Film in Water by Neutron Reflectivity, J. Phys. Conf. Ser., 83, 012023, 2007.10.
181. Y. Fujii, K. Akabori, K. Tanaka, T. Nagamura, Chain Conformation Effect on Molecular Motion at Surface in Poly(methyl Methacrylate) Films, Polym. J., 39(9), 928-934 , 2007.09.
182. K. Niihara, U. Matsuwaki, N. Torikai, H. Atarashi, K. Tanaka, H. Jinnai, A Novel Structural Analysis for A Cylinder-forming Block Copolymer Thin Film Using Neutron Reflectivity Aided By Transmission Electron Microtomography, Macromolecules, 40(19), 6940-6946, 2007.09.
183. Ken Ichi Niihara, Ukyo Matsuwaki, Naoya Torikai, Hironori Atarashi, Keiji Tanaka, Hiroshi Jinnai, A novel structural analysis for a cylinder-forming block copolymer thin film using neutron reflectivity aided by transmission electron microtomography, Macromolecules, 10.1021/ma071334c, 40, 19, 6940-6946, 2007.09, [URL], Microphase-separated structures of a poly(deuterated styrene-block-2- vinylpyridine) (dPS-b-P2VP) block copolymer in thin films were studied by neutron reflectivity (NR) and transmission electron microtomography (TEMT). The dPS-6-P2VP block copolymer shows a cylindrical morphology in the bulk state. The block copolymer was spun-coated on a Si substrate, which was extensively annealed (170°C for 14 days) before the NR experiments. The annealed thin film showed a featureless NR profile, the reflectivity monotonically decreased with the increasing scattering vector along the depth direction of the thin film, qz. The portion of the dPS-b-P2VP block copolymer thin film used in the NR experiment was examined by TEMT, from which a three-dimensional (3D) morphology of the block copolymer thin film was successfully obtained. The 3D image clearly showed that the microphase-separated structure inside the thin film had a cylindrical morphology with some order along the depth but almost no in-plane order. In order to analyze the NR profile by a conventional model fitting method, a model structure that exhibits a concentration profile is necessary as an initial "guess". In this study, two different models i. e., (i) hexagonally packed P2VP cylinders laying parallel to the Si substrate based on the known lattice parameters and (ii) experimentally obtained TEMT 3D structure, were proposed. The concentration profiles evaluated from these two models were used as the initial guesses in the fitting of the calculated profiles to the experimentally obtained NR profile, Rexp. It was found that the fitting based on the former model failed, while the fitting based on the latter one had an excellent fit to the Rexp. This result demonstrates that the microphase-separated structures that are NOT perfectly periodic nor oriented can still be analyzed by our new technique..
184. Kei Ichi Akabori, Keiji Tanaka, Noriaki Satomi, Toshihiko Nagamura, Atsushi Takahara, Tisato Kajiyama, Effects of static and dynamic forces on surface viscoelastic response of polymer films in scanning viscoelasticity microscopy, Polymer Journal, 10.1295/polymj.PJ2006230, 39, 7, 684-689, 2007.09, [URL], Scanning force microscopy with force-modulation mode enables one to gain direct insights into local viscoelastic properties at polymer surfaces. Changing modulation condition such as dynamic amplitude and frequency in addition to static normal force, surface viscoelastic response of polystyrene (PS) film was studied. If dynamic and/or static forces were/was ill-chosen, non-linearity of viscoelastic response became dominant, resulting in hole formation at the surface. On the contrary, if they were appropriately adjusted, linear viscoelastic measurement could be realized in the frequency range from 10 Hz to 4 kHz. This leads to traditional rheological analysis even at the surface..
185. Keiji Tanaka, Tawa Keiko, Study on Nano-physical Properties of Polymer Solids for the Near Future, Kobunshi, 10.1295/kobunshi.56.38, 56, 1, 2007.09, [URL].
186. Keiji Tanaka, Tawa Keiko, The Direction of My Future Research in the Field of Polymer Science, Kobunshi, 10.1295/kobunshi.56.38a, 56, 1, 2007.09, [URL].
187. 立石洋平、赤堀敬一、田中敬二、長村利彦, ポリスチレン超薄膜中における階層的分子運動特性, 高分子論文集 , 64(7), 429-436, 2007.07.
188. K. Akabori, K. Tanaka, N. Satomi, T. Nagamura, A. Takahara, T. Kajiyama, Effects of Static and Dynamic Forces on Surface Viscoelastic Response of Polymer Films in Scanning Viscoelasticity Microscopy, Polym. J. , 39(7), 684-689, 2007.07.
189. Y. Tateishi, K. Tanaka, T. Nagamura, Kinetics of Photo-induced E to Z Isomerization for Azobenzene in Films; Thickness, Molecular Weight and Temperature Effects, J. Phys. Chem. B., 111(27), 7761-7766, 2007.07.
190. 岡本泰志、泉 隆夫、青木孝司、加藤和夫、田中敬二、佐々木園、高原 淳、梶山千里, ポリブチレンテレフタレートの接着挙動におよぼす熱処理条件の影響, 日本接着学会誌, 43(7), 279-284, 2007.07.
191. Yohei Tateishi, Keiichi Akabori, Keiji Tanaka, Toshihiko Nagamura, Hierarchical thermal molecular motion in thin polymer films, KOBUNSHI RONBUNSHU, 10.1295/koron.64.429, 64, 7, 429-436, 2007.07, [URL], Hierarchical thermal molecular motion was studied in thin films of polystyrene (PS). The segmental motion in the thin films was examined by dynamic mechanical analysis. Molecular motions with a relatively small scale in the thin films were discussed on the basis of the kinetics of photoinduced trans to cis isomerization for azobenzene probes tagged to PS. Apparent glass transition temperatures generally decreased with decreasing film thickness. Although relaxation temperatures of β and γ processes in the thin films would be comparable to those in the bulk, the photoisomerization reaction of azobenzene probes became faster with decreasing thickness. Finally, a model for hierarchical thermal molecular motions in thin films was proposed on the basis of the above-mentioned results..
192. Yohei Tateishi, Keiji Tanaka, Toshihiko Nagamura, Kinetics of photoinduced E to Z isomerization of azobenzene in polystyrene films
Thickness, molecular weight and temperature effects, Journal of Physical Chemistry B, 10.1021/jp0705065, 111, 27, 7761-7766, 2007.07, [URL], E to Z (trans → cis) photoisomerization of azobenzene (Az) chromophores tagged to polystyrene (PS) in thin films was studied as functions of thickness, PS molecular weight, and temperature, using the change in absorption at 336 nm arising from the Az E isomer remaining upon ultraviolet light irradiation at 350 ± 5 nm. The photoisomerization in solid films exhibited fast and slow modes. The fractional amount of the fast mode (I 1) started to increase with decreasing film thickness once the films were thinner than a threshold value. This was explained in terms of a surface layer in which the photoisomerization reaction proceeds quickly, the effect of which becomes more noticeable with decreasing thickness due to a larger surface to volume ratio. The thickness dependence of the I1 fraction was insensitive to the molecular weight of the PS used. The thickness of the surface layer, estimated through a layer model analysis, increased with rising temperature up to 298 K. Interestingly, the surface layer markedly thickened at temperatures at which the molecular motion of PS is on a relatively small scale, namely, at the γ and β relaxation temperatures..
193. H. Atarashi, K. Akabori, A. Tanaka, M. Ozawa, K. Tanaka, T. Nagamura, Graft Polymerization Initiated by Photo-sensitizer Segregated at Surface of Polymer Film Upon Ultraviolet Irradiation, Chem. Lett. , 36(6), 808-809 , 2007.06.
194. D. Kawaguchi, K. Tanaka, N. Torikai, A. Takahara, T. Kajiyama, Surface and Interfacial Segregation in Blends of Polystyrene with Functional End Groups and Deuterated Polystyrene, Langmuir , 23(13), 7269-7275, 2007.06.
195. Hironori Atarashi, Kei Ichi Akabori, Akihiro Tanaka, Masaaki Ozawa, Keiji Tanaka, Toshihiko Nagamura, Graft polymerization initiated by photosensitizer segregated at surface of polymer film upon ultraviolet irradiation, Chemistry Letters, 10.1246/cl.2007.808, 36, 6, 808-809, 2007.06, [URL], A novel approach to surface modification of polymer films is proposed on the basis of graft polymerization initiated from photosensitizers attached to hyperbranched polymers which are localized at the film surface..
196. Yoshihisa Fujii, Hironori Atarashi, Kei Ichi Akabori, Masahiro Hino, Keiji Tanaka, Toshihiko Nagamura, Structural analysis for a poly(methyl methacrylate) ultrathin film in water by neutron reflectivity, Journal of Physics: Conference Series, 10.1088/1742-6596/83/1/012023, 83, 1, 2007.06, [URL], Density profiles of a perdeuterated poly(methyl methacrylate) (dPMMA) film spin-coated on a substrate in water (H2O) and deuterated water (D2O) were examined along the direction normal to the interface by specular neutron reflectivity (NR). Although H2O and D2O were typical non-solvents for dPMMA, their interfaces were more diffuse than the air/dPMMA interface due to the swelling caused by the sorption of H 2O and D2O molecules. An isotopic effect on aggregation structure of the dPMMA film in water was also discussed..
197. Daisuke Kawaguchi, Keiji Tanaka, Naoya Torikai, Atsushi Takahara, Tisato Kajiyama, Surface and interfacial segregation in blends of polystyrene with functional end groups and deuterated polystyrene, Langmuir, 10.1021/la700418j, 23, 13, 7269-7275, 2007.06, [URL], The effect of chain-end chemistry on surface and interfacial segregation in symmetric blends of polystyrene (hPS)/ deuterated polystyrene (dPS) has been investigated by X-ray photoelectron and secondary ion mass spectroscopy in conjunction with neutron reflectivity measurements. α,ω-Fluoroalkyl- and α,ω-carboxy-terminated polystyrenes (α,ω-hPS(R f)2 and α,ω-hPS(COOH)2) were used as end-functionalized polymers; the former possesses chain ends with lower surface energies, and the latter possesses higher surface energies compared with that of the main chain. In the case of an α,ω-hPS(R f)2/dPS blend film, α,ω-hPS(R f)2 was enriched at the surface owing to the surface localization of the Rf groups, although the surface energy of the hPS segments was slightly higher than that of the dPS ones. On the contrary, in the case of an α,ω-hPS(COOH)2/dPS blend film, dPS was preferentially segregated at the surface. This may be due to a surface depletion of COOH ends and an apparent molecular weight increase of α,ω- hPS(COOH)2 produced by a hydrogen-bonded intermolecular association of COOH ends in addition to the surface energy difference between hPS and dPS segments. Interestingly, both Rf and COOH chain ends were partitioned to the substrate interface for the α,ω-hPS(Rf) 2/dPS and α,ω-hPS(COOH)2/dPS blend films, resulting in the segregation of the hPS component at the substrate interface for both blends. The results presented imply that surface and interfacial segregation in polymer blends could be regulated by incorporating functional groups into the end portions of one component..
198. H. Atarashi, F. Ariura, K. Akabori, A. Tanaka, M. Ozawa, K. Tanaka, T. Nagamura, Interfacial Segregation of Hyper-branched Polystyrene in Mixtures of Linear Component, Trans. Mater. Res. Soc. Japan, 32(1), 231-234, 2007.04.
199. Y. Fujii, Hironori A., N. Yamada, N. Torikai, K. Tanaka, T. Nagamura, Interfacial Structure of Deuterated Poly(methyl Methacrylate) with Carbon Dioxide below the Bulk Glass Transition Temperature, Trans. Mater. Res. Soc. Japan, 32(1), 293-296, 2007.04.
200. K.Akabori, K.Tanaka, A.Takahara, T.Kajiyama, T.Nagamura, Substrate Effect on Mechanical Relaxation of Polystyrene in Ultrathin Films, J.Phys. IV France, 投稿中, 2007.02.
201. K. I. Akabori, Keiji Tanaka, Atsushi Takahara, T. Kajiyama, T. Nagamura, Substrate effect on mechanical relaxation of polystyrene in ultrathin films, European Physical Journal: Special Topics, 10.1140/epjst/e2007-00036-8, 141, 1, 173-180, 2007.02, [URL], Mechanical relaxation behavior in ultrathin polystyrene(PS) films supported on silicon oxide (SiOx) and gold (Au) substrates has been studied by dynamic viscoelastic measurement. Based on the method, effects of free surface and substrate interface on the segmental dynamics were discussed. In the case of thin PS films with a thickness of approximately 200 nm, αa-relaxation process corresponding to the segmental motion did not show any deviation from the bulk behavior. Incontrast, for the films thinner than about 50 nm, the relaxation time distribution for the αa-process became broader, probably due toa mobility gradient in the surface and interfacial regions. When we sandwiched an ultrathin PS film between SiOx layers, another relaxation process, in addition to the original αa-process, appeared at ahigher temperature side that we assigned to the interfacial αa-relaxation process. However, this was never seen for an ultrathin PS film between Au layers, implying that restriction from the substrate interface might be weak in this case..
202. Kei Ichi Akabori, Keiji Tanaka, Toshihiko Nagamura, Atsushi Takahara, Tisato Kajiyama, Thermal molecular motion in polystyrene thin and ultrathin films by dynamic viscoelastic measurement, Journal of Central South University of Technology (English Edition), 10.1007/s11771-007-0279-6, 14, 1 SUPPL., 346-349, 2007.02, [URL], Segmental motion in polystyrene (PS) thin and ultrathin films supported on substrates was studied by dynamic viscoelastic measurement. A polymer film, which has the thickness comparable to or less than twice of radius of gyration of an unperturbed chain (2R g), is defined as an ultrathin film. In the case of PS, α a-relaxation process corresponding to the segmental motion was generally observed at approximately 380 K. Even for both the PS thin and ultrathin films, the α a-absorption peak was clearly observed. A rheological analysis reveals that the α a-relaxation behavior for the thin films with the thickness of about 200 nm is the same as that of the bulk sample. On the contrary, in the case of the PS ultrathin films, the α a-absorption peak on temperature-loss modulus (E) curve is broadened toward both lower and higher temperature sides. This can be interpreted by taking into account that the segmental motion in the vicinity of surface and interface is detectable for such ultrathin films, which should be faster and slower than that in the bulk, respectively. And, it is found that the apparent activation energy (ΔH) for the α a-relaxation in the ultrathin films becomes smaller than the bulk value probably due to the surface effect. Finally, an interfacial effect on the ΔH was studied by using different substrates. When the interaction between PS and substrate becomes stronger, the ΔH value for the α a-relaxation in the ultrathin films increases. The results imply that the segmental motion in the polymer ultrathin films is strongly influenced by surface and interfacial effects..
203. Kazuo Kato, Takashi Aoki, Yasushi Okamoto, Keiji Tanaka, Atsushi Takahara, Reliability analysis of adhesive for PBT-epoxy interface, 2007 World Congress
2007 World Congress
, 2007, PBT (polybutylene terephthalate) and epoxy adhesive, which both have superior heat resistance and environmental resistance, are a representative combination now being applied to many parts. Generally, PBT is annealed after molding at a temperature above the glass transition temperature to ensure dimensional stability when in use. But in this case, this process decreases the adhesive strength between PBT and epoxy. This study analyzes the adhesion degradation mechanism in this system and a countermeasure technology is proposed. Regarding this PBT-epoxy adhesion degradation mechanism, focus is placed on changes in the fracture surface, which is analyzed before and after annealing. From this analysis it becomes clear that generation of a WBL (weak boundary layer) is caused by non-crystallization and a migration of the PBT functional group on the adhesion surface layer. According to this mechanism, it is clear that control of the functional group on the surface layer and reforming of a new functional group are very effective ways to maintain adhesive strength after annealing..
204. Kei Ichi Akabori, Daisuke Baba, Kazuhiro Koguchi, Keiji Tanaka, Toshihiko Nagamura, Relation between the adhesion strength and interfacial width for symmetric polystyrene bilayers, Journal of Polymer Science, Part B: Polymer Physics, 10.1002/polb.21020, 44, 24, 3598-3604, 2006.12, [URL], Polystyrene (PS) bilayers were prepared and were adhered at a temperature between the surface and bulk glass-transition temperatures for a given time. Then, the interfacial adhesion strength (GL) was examined with a conventional lapshear measurement. GL first increased with increasing adhesion time and then reached a constant value. This result implied that the segments moved across the interface, to a certain depth, even at a temperature below the bulk glass-transition temperature. To confirm this, the interfacial evolution for the PS/deuterated PS bilayers was examined with dynamic secondary-ion mass spectrometry. The GL value was linearly proportional to the thickness of the interfacial adhesion layer. Finally, we propose a strategy for regulating the adhesion strength based on the chain-end chemistry..
205. Masahiro Hino, Masaaki Kitaguchi, Hirotoshi Hayashida, Yuji Kawabata, Seiji Tasaki, Toru Ebisawa, Dai Yamazaki, Ryuji Maruyama, Keiji Tanaka, Naoya Torikai, Rintaro Inoue, Toshiji Kanaya, A test of MIEZE-reflectometer for study of surface and interface, Physica B: Condensed Matter, 10.1016/j.physb.2006.05.388, 385-386, 1125-1127, 2006.11, [URL], We have installed a MIEZE-type spin echo spectrometer at the C3-1-2-2 (MINE1) port at the JRR-3 M in the Japan Atomic Energy Agency. By combining neutron reflectometry and the MIEZE, it is possible to detect inelastic and quasi-elastic scattering on the surface and at the interface. We have succeeded in measuring a MIEZE signal for which the Fourier time is up to 0.8 ns. Though the Fourier time is small, we tested several samples by the MIEZE reflectometer..
206. Hiroshi Morita, Keiji Tanaka, Tisato Kajiyama, Toshio Nishi, Masao Doi, Study of the glass transition temperature of polymer surface by coarse-grained molecular dynamics simulation, Macromolecules, 10.1021/ma052632h, 39, 18, 6233-6237, 2006.09, [URL], The glass transition temperature at the surface of polymer film is studied by the coarse-grained molecular dynamics simulation. By the analysis of the segmental motion, the glass transition temperatures at the surface region and that in the bulk region are determined separately. The glass transition at the surface region is found to be lower than that in the bulk region. The molecular weight dependence of the glass transition temperature obtained by the simulation agrees well with that obtained by the scanning force microscopic measurements..
207. K.Akabori, D.Baba, K.Koguchi, K.Tanaka, T.Nagamura, Relation between the Adhesion Strength and Interfacial Width for Symmetric Polystyrene Bilayers, J.Polym. Sci. B: Polym. Phys., 印刷中, 2006.08.
208. Daisuke Kawaguchi, Keisuke Masuoka, Atsushi Takano, Keiji Tanaka, Toshihiko Nagamura, Naoya Torikai, Robert M. Dalgliesh, Scan Langridge, Yushu Matsushita, Comparison of interdiffusion behavior between cyclic and linear polystyrenes with high molecular weights, Macromolecules, 10.1021/ma060652t, 39, 16, 5180-5182, 2006.08, [URL], The interdiffusion behavior between cyclic and linear polystyrenes with high molecular weight based on dynamic secondary ion mass spectroscopy (DSIMS) in conjunction with neutron reflectivity (NR) measurements was investigated. Polymers used in this study are monodisperse cyclic and linear PSs (c-hPS, 1-hPS) and those deuterated counterparts (c-dPS, 1-dPS). Time evolution of interfacial thickness with annealing was evaluated by NR and DSIMS. The broadening of the (c-hPS/c-dPS) interface takes place much more rapidly than that of corresponding linear ones. The diffusion of cyclic polystyrene is much faster than that of linear polystyrene. Both thickness of (c-hPS/c-dPS) and (1-hPS/1-dPS) interfaces increase with increasing temperature at 120°C, and that of (c-hPS/c-dPS) bilayer films is much higher than that of (1-hPS/1-dPS) ones at any given temperature..
209. Keiji Tanaka, Glass transition of polymers in confined systems, KOBUNSHI RONBUNSHU, 10.1295/koron.63.539, 63, 8, 539-547, 2006.08, [URL], In this paper, glass transitions of polystyrene (PS) in confined geometry such as ultrathin state, surface and interface were studied. Dynamic mechanical analysis was successfully used to characterize polymer ultrathin films supported on substrates. This method allowed us to uncover the effects of the free surface and the substrate interface on the segmental dynamics in PS films with various thickness. As the film thickness decreased, the distribution of relaxation times for the segmental motion became broader, a change mainly due to surface and interfacial effects. The results obtained in this study imply that two contrasting effects exist: the effect of the free surface accelerates the segmental motion, whereas interfacial interaction produce the opposite effect. This was also confirmed by independent experiments related to glass transition temperature at the surface and the interface by scanning force microscopy and time- and space-resolved fluorescence spectroscopy, respectively..
210. Keiji Tanaka, Yu Tsuchimura, Kei Ichi Akabori, Fuyuki Ito, Toshihiko Nagamura, Time- And space-resolved fluorescence study on interfacial mobility of polymers, Applied Physics Letters, 10.1063/1.2335593, 89, 6, 2006.08, [URL], Segmental mobility of a typical amorphous polymer, polystyrene, at the interface with a solid substrate was examined noninvasively by fluorescence lifetime measurement using evanescent wave excitation. Glass transition temperature (Tg) was discernibly higher at the interface than in the bulk. Measurements at different incident angles of excitation pulses revealed that Tg became higher the closer to the interface. This is the observation for a Tg gradient of polymers at the interface..
211. D.Kawaguchi, K.Masuoka, A.Takano, K.Tanaka, T.Nagamura, N.Torikai, R.M.Dalgliesh, S.Langridge, Y.Matsushita, Comparison of Interdiffusion Behavior between Cyclic and Linear Polystyrenes with High Molecular Weights, Macromolecules, 39:5180-5182, 2006.01.
212. 田中敬二, 束縛場における高分子のガラス転移, 高分子論文集, 63:539-547, 2006.01.
213. K.Tanaka, Y.Tshchimura, K.Akabori, F.Ito, T.Nagamura, Time-and Space-resolved Fluorescene Study on Interfacial Mobility of Polymers, Appl. Phys. Lett., 89:061919-1-2, 2006.01.
214. H.Morita, K.Tanaka, T.Kajiyama, T.Nishi, M.Doi, Study of the Glass Transition Temperature of Polymer Surface by Coase-grained Molecular Dynamics Simulation, Macromolecules, 39:6233-6237, 2006.01.
215. Daisuke Kawaguchi, Atsushi Takano, Yushu Matsushita, Naoya Torikai, Keiji Tanaka, Toshihiko Nagamura, Robert Dalgliesh, Sean Langridge, Comparison of molecular motion between linear polystyrenes and cyclic polystyrenes with same molecular weight, 55th Society of Polymer Science Japan Symposium on Macromolecules
55th SPSJ Symposium on Macromolecules
, 55, 3131-3132, 2006, Time evolution of interfacial thicknesses between a cyclic polystyrene (c-hPS) / its deuterated counterpart (c-dPS) and a linear polystyrene (1-hPS) / its deuterated counterpart (1-dPS) bilayer films was investigated by dynamic secondary ion mass spectrometry (DSIMS) and neutron reflectivity (NR). The interfacial thickness of (c-hPS/c-dPS) film was significantly larger than that of (1-hPS/1-dPS) film at any given annealing time, indicating that the diffusion constant of c-PS is constantly larger than that of 1-PS. It might be explained that weaker topological constraint comes from the entanglement for the c-PS than for the 1-PS..
216. Yasushi Okamoto, Kazuo Kato, Takashi Aoki, Takao Izumi, Keiji Tanaka, Osami Sakata, Atsushi Takahara, Tisato Kajiyama, Effect of annealing treatment and surface treatment on adhesion behavior of poly(butylene terephthalate), 55th SPSJ Annual Meeting
Polymer Preprints, Japan - 55th SPSJ Annual Meeting
, 55, 1136, 2006, Influence of annealing treatment on adhesion behavior of poly(butylene terephthalate) (PBT) with epoxy adhesive was studied. The tensile adhesion strength decreased after the annealing treatment of PBT. In the case of the untreated PBT, the failure depth after the failure was not clearly defined. Once the PBT was annealed, the average failure depth turned to be 4 nm. The above results imply that the failure mechanism for the system transformed from interfacial failure to cohesive fracture upon annealing treatment. This can be easily understood by taking into account that a mechanically weak layer is formed in the surface region of PBT after the annealing. Such a weak boundary layer was observed by scanning viscoelasticity microscopy. Improvement of adhesive property was confirmed by surface treatment..
217. Yasushi Okamoto, Kazuo Kato, Takashi Aoki, Takao Izumi, Keiji Tanaka, Atsushi Takahara, Tisato Kajiyama, Influence of plasma treatment on adhesion behavior of poly(butylene terephthalate), 55th Society of Polymer Science Japan Symposium on Macromolecules
55th SPSJ Symposium on Macromolecules
, 55, 3442, 2006, An effect of surface treatment on adhesion behavior of poly (butylene terephthalate) (PBT) with epoxy adhesive was studied. In general, PBT is annealed at a temperature above the glass transition temperature to obtain dimensional stability for the practical use. However, such an annealing procedure makes the adhesion properties poorer. In this study, we demonstrate that tensile adhesive strength for annealed PBT could be improved through plasma treatment. Tensile adhesive strength increased with increasing surface density of C-O and COO groups, which were quantitatively detected by XPS. Finally, it was concluded that chemical interaction between carboxyl and/or ester groups of PBT and hydroxyl groups of epoxy adhesive was a responsible factor in improving adhesive strength between PBT and epoxy adhesive..
218. Masaya Hikita, Tetsuya Nakamura, Keiji Tanaka, Tisato Kajiyama, Atsushi Takahara, Liquid repellent properties of patterned surfaces and their applications to polymeric materials, 55th SPSJ Annual Meeting
Polymer Preprints, Japan - 55th SPSJ Annual Meeting
, 55, 1264, 2006, It was studied how liquid repellent properties can be controlled on the basis of roughness at surfaces. Ultrafine-patterned surfaces were prepared by the photolithography. The surfaces were fully covered with fluoroalkyl silane coupling agent by chemical vapor deposition (CVD) for about two hours. Contact angle to water increased as increasing pitch of the pattern. The relation between water contact angle and pitch was well expressed by the Cassie mode, where assumed that the space between solid surface and water was occupied by air. Contact angle to dodecane was neither in agreement with Wenzel nor Cassie's modes. Instead, in the case of dodecane, both modes should be combined to reproduce the experimental results. Hence, it can be claimed that factors such as increase in surface area and formation of air layer at the interface between liquid and surface are important for excellent liquid repellent properties..
219. Keiichi Akabori, Kazuyuki Oya, Hiroki Murase, Keiji Tanaka, Atsushi Takahara, Tisato Kajiyama, Nano-rheological analysis of polymer cross-section films prepared by a mechanical cutting method, 55th SPSJ Annual Meeting
Polymer Preprints, Japan - 55th SPSJ Annual Meeting
, 55, 1270, 2006, A cross-section film of a symmetric diblock copolymer, in which lamellar structure was formed, was successfully prepared by a mechanical cutting method using a sharp diamond knife. In this method, the knife was obliquely pushed into the sample from the surface side. The oblique angle was precisely controlled to be 0.57 deg. Thus, periodic lamellar structure was shown up at the surface of the cross-section film Then, scanning viscoelasticity microscopy (SVM), which can image viscoelastic information at the surface, was applied to the cross-section film. Finally, it was demonstrated that a combination of SVM and mechanical cutting method enabled one to gain direct insight into the depth information for structure and physical properties of the diblock copolymer film along the direction normal to the surface..
220. Kazuyuki Oya, Keiichi Akabori, Hiroki Murase, Keiji Tanaka, Atsushi Takahara, Tisato Kajiyama, Nano-rheological analysis of polymer thin films prepared by gradient shaving method, 55th Society of Polymer Science Japan Symposium on Macromolecules
55th SPSJ Symposium on Macromolecules
, 55, 3095-3096, 2006, In order to investigate structure of diblock copolymer thin film, gradient shaved surface was prepared by using Surface And Interfacial Cutting Analysis System (SAICAS). The scanning viscoelasticity microscopic observation of sliced film revealed the alternate lamellar structures with different mechanical properties in the depth direction..
221. Tomoyuki Koga, Shigekazu Yasutake, Keiji Tanaka, Keiichi Akabori, Kazunori Andou, Tisato Kajiyama, Atsushi Takahara, Evaluation of surface mechanical properties of organic ultrathin films using scanning force microscope, 54th SPSJ Symposium on Macromolecules
54th SPSJ Symposium on Macromolecules - Polymer Preprints, Japan
, 54, 3840-3841, 2005.12, Surface mechanical properties of polystyrene (PS) film prepared from single droplet of PS solution by ink-jet (IJ) method, and [PS / Polybutadiene (BDA)] (60/40, w/w) blend film were investigated by scanning force microscope. The scanning viscoelesticity microscopic measurements at various temperatures clarified that the relative difference of contrast of the PS and the PBD phase surface becomes small with an increase of temperature. This is due to the relative difference of elasticity of PS and PBD phases. Based on the temperature dependent lateral force measurements, the surface of the PS film prepared by IJ method was in a glass-rubber transition state even at 343 K, in spite of that the bulk Tg was far above 343 K [Tg (bulk)=378 K]. Similar temperature dependence of lateral force was also observed on the PS film prepared by spin-coating method..
222. Atsushi Sakai, Keiji Tanaka, Yoshihisa Fujii, Toshihiko Nagamura, Tisato Kajiyama, Erratum
Structure and thermal molecular motion at surface of semi-crystalline isotactic polypropylene films (Polymer (2005) 46 (429-437) DOI: 10.1016/j.polymer.2004.11.021), Polymer, 10.1016/j.polymer.2004.12.036, 46, 5, 2005.02, [URL].
223. A.Sakai, K.Tanaka, Y.Fujii, T.Nagamura, T.Kajiyama, Structure and Thermal Molecular Motion at Surface of Semi-Crystalline Isotactic Polypropylene Films, Polymer, 10.1016/j.polymer.2004.11.021, 46, 2, 429-437, 46:429-437, 2005.01.
224. H.Yakabe, K.Tanaka, T.Nagamura, S.Sasaki, O.Sakata, A.Takahara, T.Kajiyama, Grazing Incidence X-ray Diffraction Study on Surface Crystal Structure of Polyethylene Thin Films, Polym. Bull., 10.1007/s00289-004-0329-2, 53, 3, 213-222, 53:213-222, 2005.01.
225. H.Yokoyama, T.Miyamae, S.Han, T.Ishizone, K.Tanaka, A.Takahara, N.Torikai, Spontaneously Formed Hydrophilic Surfaces by Segregation of Block Copolymers with Water-Soluble Blocks, Macromolecules, 10.1021/ma050473w, 38, 12, 5180-5189, 38:5180-5189, 2005.01.
226. M.Hikita, K.Tanaka, T.Nakamura, T.Kajiyama, A.Takahara, Super Liquid Repellent Surfaces Prepared by Colloidal Silica Nano-Particles Covered with Fluoroalkyl Groups, Laugmuir, 10.1021/la050901r, 21, 16, 7299-7302, 21:7299-7302, 2005.01.
227. 疋田真也、田中敬二、中村哲也、高原 淳、梶山千里, フッ素−シリカハイブリッドコーティングによる透明超撥水表面の形成, 表面科学, 26:559-563, 2005.01.
228. 中原重樹、本岡正則、田中敬二、高原 淳、梶山千里, 走査プローブ顕微鏡による(ポリプロピレン/エラストマー粒子)系ブレンド界面の評価, 高分子論文集, 62:432-434, 2005.01.
229. K.Akabori, K.Tanaka, T.Nagamura, A.Takahara, T.Kajiyama, Molecular Motion in Ultrathin Polystyrene Films: Dynamic Mechanical Analysis of Surface and Interfacial Effects, Macromolecules, 10.1021/ma051143e, 38, 23, 9735-9741, 38:9735-9741, 2005.01.
230. Shigeki Nakahara, Masanori Motowoka, Keiji Tanaka, Atsushi Takahara, Tisato Kajiyama, Evaluation of interfacial structure in blends of polypropylene and elastomer by scanning force mircroscopy, KOBUNSHI RONBUNSHU, 10.1295/koron.62.432, 62, 9, 432-434, 2005.01, [URL], Flat cross-sections of (polypropylene/elastomer) blends were prepared by ultamicrotoming at 150 K. Then, scanning force microscopy (SFM) was applied to each cross-section to evaluate the interfacial thickness between the two phases in the blend. For this purpose, a viscoelastic mode was superior to a conventional topographic mode. The results obtained well reflected the solubility between the two components. Finally, transmission electron microscopy was applied to the sample. The TEM observations supported what was suggested on the basis of SFM results..
231. Yasushi Okamoto, Kazuo Kato, Takashi Aoki, Takao Izumi, Keiji Tanaka, Osami Sakata, Sono Sasaki, Atsushi Takahara, Tisato Kajiyanm, An effect of surface treatment on adhesion behavior of poly (butylene terephthalate), 54th SPSJ Symposium on Macromolecules
54th SPSJ Symposium on Macromolecules - Polymer Preprints, Japan
, 54, 3289-3290, 2005, An effect of surface treatment on adhesion behavior of poly (butylene terephthalate) (PBT) with epoxy adhesive was studied. In general, PBT is supposed to be annealed at a temperature above the glass transition temperature to obtain dimensional stability for the practical use. However, such an annealing procedure makes the adhesion properties poorer. In this study, we demonstrate that tensile adhesive strength for annealed PBT could be improved through UV irradiation or chemical etching treatment. Tensile adhesive strength increased with increasing surface density of C-O and C=O groups, which were quantitatively detected by XPS. Finally, it was concluded that chemical interaction between carboxyl and/or ester groups of PBT and hydroxyl groups of epoxy adhesive was a responsible factor in improving adhesive strength between PBT and epoxy adhesive..
232. Keigo Aoi, Takaaki Fukui, Yoshiharu Otsuka, Keiji Tanaka, Toshihiko Nagamura, Architecture and shape control of nanoobjects based on amphiphilic dendrimers, 54th SPSJ Symposium on Macromolecules
54th SPSJ Symposium on Macromolecules - Polymer Preprints, Japan
, 54, 2715-2716, 2005, In the field of nanotechnology and nanoscience, dendrimers are key compounds having well-defined chemical structure. We nave already reported synthesis of globular carbohydrate macro molecule "sugar ball" which is applicable to gene and drug carriers [1-4]. Amphiphilic surface-sugar- substituted surface-block dendrimers have been also designed, synthesized and characterized [4]. Supramolecular architeucture based on amphiphilic dendrimers is important to create shape controlled smart nanoobjects[5]. The present report deals with synthesis and assembly of amphiphilic sugar-substituted poly(ethylene glycol) dendrimers. The dendrimers were synthesized by the reaction of N-acetyl-D-glucosamine, galactose, and lactose derivatives with poly(ethylene glycol) dendrimer having a hydroxy group and alkyl groups at the core and the surface, respectively, wnich were prepared by convergent method. The sugar moieties and the poly(ethylene glycol) dendrimer branches are regarded as hydrophilic parts, whereas the alkyl groups act as hydrophobic groups. Although hydrophobicity of the amphiphilic dendrimers is high, nanoparticles based on the amphiphilic dendrimers can be prepared by irradiation of ultrasonic wave. Fortunately the particle size, which is measured using DLS, could be controlled around ca. 200 nm. Monolayer of the amphiphilic dendrimers was successfully formed at the air/water interface. Intermolecular distance, i.e., intersugar distance, of the monolayer was found to be controlled around 2 nm by changing generation and hydrophobic groups of the dendrimers..
233. Keiichi Akabori, Keiji Tanaka, Toshihiko Nagamura, Atsushi Takahara, Tisato Kajiyama, Effect of substrate interface on mechanical relaxation behavior in polymer ultrathin films, 54th SPSJ Annual Meeting 2005
54th SPSJ Annual Meeting 2005 - Polymer Preprints, Japan
, 54, 925, 2005, Mechanical relaxation behavior of polystyrene (PS) and poly (2-vinylprydine) (P2VP) thin and ultrathin films on substrates was examined. Even in the case of the ultrathin films, the α2-relaxation process corresponding to the segmental motion was successfully observed. However, the αa-absorption peak was broadened toward lower and higher temperature sides because of surface and interfacial effects. Interestingly, when a PS ultrathin film was sandwiched between SiOx layers, an additional peak come up with the interfacial segmental motion appeared at the higher temperature side. In the case of the P2VP ultrathin films on the SiOx substrates, the interfacial effect became remarkable due to the strong attractive interaction between chains and the substrate. Finally, it was concluded that chain mobility in the interfacial region was depressed in comparison with that in the internal bulk phase..
234. Yasushi Okamoto, Kazuo Kato, Takao Izumi, Keiji Tanaka, Osami Sakata, Atsushi Takahara, Tisato Kajiyama, Influence of annealing treatment on adhesion behavior of poly(butylene terephthalate), 54th SPSJ Annual Meeting 2005
54th SPSJ Annual Meeting 2005 - Polymer Preprints, Japan
, 54, 879, 2005, Influence of annealing treatment on adhesion behavior of poly(butylene terephthalate) (PBT) with epoxy adhesive was studied. The tensile adhesion strength decreased after the annealing treatment of PBT. In the case of the untreated PBT, the failure depth after the failure was not clearly defined. Once the PBT was annealed, the average failure depth turned to be 4 nm. The above results imply that the failure mechanism for the system transformed from interfacial failure to cohesive fracture upon annealing treatment. This can be easily understood by taking into account that a mechanically weak layer is formed in the surface region of PBT after the annealing. Such a weak boundary layer was observed by grazing incidence X-ray diffraction measurement..
235. Keiji Tanaka, Polymer nano-adhesion promoted by surface molecular motion, 54th SPSJ Annual Meeting 2005
54th SPSJ Annual Meeting 2005 - Polymer Preprints, Japan
, 54, 109-111, 2005, Polymer nano-adhesion was studied. Polystyrene (PS) bilayer was prepared by attaching original two PS film surfaces together, and was annealed at a temperature between surface and bulk glass transition temperatures for a given time. Discernible interfacial adhesion strength (G) was observed, and was proportional to the interfacial width of a few nanometers measured by dynamic secondary ion mass spectrometry. This means that G at the (PS/PS) bilayer interface is mainly governed by interfacial thickening. Then, nano-adhesion test in between PSs was made using scanning force microscopy. The G value so obtained was larger than that for the bilayer by approximately 500 times under the same condition. The difference was accounted for by the completeness of the interfacial formation..
236. Keiichi Akabori, Hiroki Murase, Keiji Tanaka, Atsushi Takahara, Tisato Kajiyama, Quantitative evaluation of nano-mechanical properties at polymer surfaces based on scanning viscoelasticity microscopy, 54th SPSJ Symposium on Macromolecules
54th SPSJ Symposium on Macromolecules - Polymer Preprints, Japan
, 54, 3291-3292, 2005, A mechanical model analysis for scanning viscoelasticity microscopic (SVM) measurement under various conditions was carried out to quantitatively evaluate spring constants of polymer surfaces. Experiment was made at room temperature using polystyrene films with different molecular weights. When the sample surface was in a glassy state, that is, in an elastic regime, a series model composed of two springs with a cantilever and the sample surface could well express the SVM vibration system. In contrast, when the surface was in a viscoelastic regime, a viscous component must introduced into the model in order to analyze the experimental results. Based on fitting parameters for the analysis, the spring constants for the PS surfaces were successfully extracted. Consequently, the spring constants of the surfaces were lower than the bulk value by a few decades. Finally, it can be claimed that surface nano-mechanical properties are essentially different from the corresponding bulk ones..
237. Keuchi Akabori, Hiroki Murase, Keiji Tanaka, Atsushi Takahara, Tisato Kajiyama, Quantitative evaluation of spring constant of a cantilever based on scanning viscoelasticity microscopy, 54th SPSJ Annual Meeting 2005
54th SPSJ Annual Meeting 2005 - Polymer Preprints, Japan
, 54, 936, 2005, A mechanical model analysis was conducted to evaluate quantitatively spring constants for cantilevers and polymer surface via scanning viscoelasticity microscopic (SVM) measurement. The amplitude of dynamic displacement was set to be 5 nm, and the frequency was varied in the range of 101 - 2×103 Hz. Under such the condition, the cantilevers and the polystyrene (PS) surface exhibited elastic nature. An analysis using mechanical model could well reproduce the experimental results. Based on fitting parameters for the analysis, the spring constants for the cantilevers and the PS surface were extracted. Finally, it was concluded that surface mechanical properties in polymer films would be essentially different from the corresponding bulk ones..
238. Masaya Hikita, Tetsuya Nakamura, Keiji Tanaka, Atsushi Takahara, Tisato Kajiyama, Super-water-repellent coating on polymer substrates using fluorosilane-silica hybrid materials, 54th SPSJ Annual Meeting 2005
54th SPSJ Annual Meeting 2005 - Polymer Preprints, Japan
, 54, 1573, 2005, The purpose of this study is to develop transparent super-water-repellent surfaces with a simple way and to apply this coating to polymer substrates. Super-water-repellent surfaces are generally made by controlling chemistry and roughness at the surface. In this study, surface roughness was controlled by the content of colloidal silica particles in a sol-gel thin film covered with fluoroalkyl silane coupling agent. When the fractional amount of colloidal silica was in the range of 10-30 wt%, root mean square roughness at the surface by AFM was around 30-70 nm. X-ray photoelectron spectroscopy revealed that these surfaces were covered with fluoroalkyl groups. Consequently, these surfaces exhibit excellent water repellencies such as contact angles of 150 deg. to water. This coating procedure can be applied to transparent polymer substrates such as poly(ethyleneterephtarate) (PET) films. In that case, transparency and durability of the sol-gel layer on the PET film are sufficient enough to be applied for practical use..
239. Yoshihisa Fujii, Kazuhiro Koguchi, Keiji Tanaka, Toshihiko Nagamura, Atsushi Takano, Yushu Matsushita, Tisato Kajiyama, Surface relaxation behavior in cyclic polystyrene films, 54th SPSJ Annual Meeting 2005
54th SPSJ Annual Meeting 2005 - Polymer Preprints, Japan
, 54, 928, 2005, Well-defined cyclic polystyrenes (c-PS) with various molecular masses were prepared by the reaction of linear polystyrene with two end vinyl groups and potassium naphthalenide as a coupling agent. Then, surface relaxation behavior in c-PS films was examined by lateral force microscopy (LFM). The αa-relaxation process corresponding to the segmental motion was clearly observed at the surface in the c-PS films. Surface glass transition temperature so obtained was approximately 300 K, which was lower than the bulk value, and was independent of the molecular weight due to the absence of chain ends. The results indicate that the molecular motion at the polystyrene surface is activated by not only chain ends but also other factors..
240. Hideaki Yokoyama, Takayuki Miyamae, Seok Han, Takashi Ishizone, Atsushi Takahara, Keiji Tanaka, Naoya Torikai, Surface segregation of watersoluble-hydrophobic block copolymers, 54th SPSJ Annual Meeting 2005
54th SPSJ Annual Meeting 2005 - Polymer Preprints, Japan
, 54, 974, 2005, A block copolymer of deuterated polystyrene (dPS) and 2-[2-(2- methoxyethoxy)ethoxy]ethyl methacrylate (PME3MA) spontaneously exposes the PME3MA block, which is soluble in water, to the surface in a vacuum. dPS-PME3MA mixed with polystyrene (PS) segregates to the PS surface spontaneously and changes the hydrophobic PS surface into hydrophilic surface. The detail of the segregation will be discussed..
241. Hirohiko Yakabe, Keiji Tanaka, Toshihiko Nagamura, Tisato Kajiyama, Thermal molecular motion of polyethylene thin films, 54th SPSJ Annual Meeting 2005
54th SPSJ Annual Meeting 2005 - Polymer Preprints, Japan
, 54, 926, 2005, Melting and relaxation behaviors in thin films of high-density and linear low-density polyethylene (HDPE and LLDPE) were examined by microthermal analysis and dynamic viscoelastic measurements, respectively. Melting point (T m) in HDPE and LLDPE films, respectively, increased and decreased with decreasing thickness. In the case of the HDPE films, the amorphous content decreased with decreasing thickness. This leads to that molecular motion of chains involved in the crystalline region is depressed with decreasing thickness. In contrast, although the amorphous content also decreased with decreasing thickness for the LLDPE films, it is not so small. Invoking that molecular motion in the amorphous region becomes active and dominates with decreasing film thickness, it can be understood that T m decreased with thickness for the LLDPE films..
242. Tisato Kajiyama, Ken Kojio, Keiji Tanaka, Aggregation states and molecular motion of polymer ultrathin films prepared at the air/water interface, Advances in Colloid and Interface Science, 10.1016/j.cis.2004.09.007, 111, 3 SPEC. ISS., 159-179, 2004.12, [URL], The preparation of poly(amido amine) (PAMAM) dendrimer monolayers at the air/water interface was analyzed. Investigations show the transfer of PAMAM dedrimer monolayers from the air side onto hydrophobic silicon wafers, which were treated by the horizontal lifting method. X-ray reflectivity, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) techniques were used to study the aggregation states in the PAMAM monolayers. The results show that the PAMAM molecules sit on the substrate with an oblate shape in which the hydrophilic core and hydrophobic alkyl end groups were towards the substrate and air sides..
243. Keiji Tanaka, Study on Surface Glass Transition Behavior in Monodisperse Polystyrene Films, Nihon Reoroji Gakkaishi, 10.1678/rheology.32.17, 32, 1, 17-25, 2004.05, [URL], Surfaces in polymeric materials play an important role in many technological applications. Hence, systematical understanding of aggregation states and physical properties at the surfaces is of pivotal importance as the first benchmark so that highly functionalized polymeric materials based on surface peculiarity can be promisingly designed and constructed. Nevertheless, surface properties, especially rheological properties, had not been studied until early 90s because of technical difficulties. In 1993, we started to embark on this intriguing and challenging issue by mainly scanning force microscopy using monodisperse polystyrene (PS) solid films. Consequently, conclusions obtained thus far are consistently arrived that molecular motion at the PS surfaces is thermally activated in comparison with the corresponding internal bulk region. However, it is far from clear for the moment what the whole picture of such peculiar surface mobility is, although we believe that some parts of it have been successfully clarified to date. Here, experimental methods to examine surface rheological properties, which we have proposed, are mentioned at first, and then, essential points of what we have established are discussed..
244. T.Kajiyama, K.Tanaka, A.Takahara, Analysis of Surface Mobility in Polystyrene Films with Monodisperse and Bimodal Molecular Weights by Lateral Force Microscopy, J. Polym. Sci. Part A: Polym. Chem., 10.1002/pola.10873, 42, 3, 639-647, 42:639-647, 2004.01.
245. H.Yokoyama, K.Tanaka, A.Takahara, T.Kajiyama, K.Sugiyama, A.Hirao, Surface Structure of Asymmetric Fluorinated Block Copolymers: Poly[styrene-block-4-(perfluorooctylpropyloxy)styrene], Macromolecules, 10.1021/ma035191f, 37, 3, 939-945, 37:939-945, 2004.01.
246. K.Tanaka, F.Ariura, T.Nagamura, T.Kajiyama, Further Study of Chain End Effect on Surface Mobility in Monodisperse Polystyrene Films, Polymer J., 10.1295/polymj.36.498, 36, 6, 498-501, 36:498-501, 2004.01.
247. M.Hikita, K.Tanaka, T.Nagamura, T.Kajiyama, Aggregation States and Surface Wettability in Films of Poly(styrene-block-2-perfluooctyl ethyl acrylate)Diblock Copolymers Synthesized by Atom Transfer Radical Polymerization, Langmuir, 10.1021/la049556g, 20, 13, 5304-5310, 20:5304-5310, 2004.01.
248. N.Hosaka, K.Tanaka, H.Otsuka, A.Takahara,, Influence of the Addition of Silsesquioxane on the Dewetting Behavior of Polystyrene Thin Film, Compos. Interface., 10.1163/1568554041738157, 11, 4, 297-306, 11:297-306, 2004.01.
249. T.Izumi, K.Tanaka, R.Narita, S.Horiuchi, A.Takahara, T.Kajiyama, Annealing Effect on Adhesion Properties of Poly(butylene Terephthalate), Compos. Interface., 10.1163/1568554041738166, 11, 4, 325-333, 11:325-333, 2004.01.
250. K.Tanaka, Y.Tateishi, T.Nagamura, Photoisomerization of Azobenzene Probes Tagged to Polystyrene in Thin Films, Macromolecules, 10.1021/ma048579z, 37, 22, 8188-8190, 37:8188-8190, 2004.01.
251. D. Kawaguchi, K. Tanaka, T. Kajiyama, A. Takahara, S. Tasaki, Surface composition control via chain end segregation in blend films of polystyrene and poly(vinyl methyl ether), Macromolecules, 10.1021/ma034117u, 36, 18, 6824-6830, 36 (18): 6824-6830, 2003.09.
252. Tisato Kajiyama, Daisuke Kawaguchi, Keiji Tanaka, Surface Mobility in Monodisperse Polystyrene Films, Macromolecular Symposia, 10.1002/masy.200351111, 201, 95-102, 2003.09, [URL], Surface dynamics in monodisperse polystyrene films was examined by lateral force microscopy in conjunction with dynamic secondary ion mass spectroscopy. Glass transition temperature, Tg, at the surface was markedly lower than the corresponding bulk Tg. Also, it was shown that polymer chains present at the surface could diffuse even at a temperature below the bulk Tg. The surface depth, in which molecular motion was activated, was of the order of 5 nm..
253. K. Tanaka, K. Hashimoto, T. Kajiyama, A. Takahara, Visualization of active surface molecular motion in polystyrene film by scanning viscoelasticity microscopy, Langmuir, 10.1021/la034542g, 19, 17, 6573-6575, 19 (17): 6573-6575, 2003.08.
254. K.Akabori, K.Tanaka, T.Kajiyama, A.Takahara, Anomalous Surface Relaxation Process in Polystyrene Ultrathin Films, Macromolecules, 10.1021/ma034001y, 36, 13, 4937-4943, 36 (13): 4937-4943, 2003.07.
255. Tisato Kajiyama, Keiji Tanaka, Atsushi Takahara, Nano-rheological properties of polymeric solid surfaces, Nihon Reoroji Gakkaishi, 10.1678/rheology.31.33, 31, 1, 33-40, 2003.06, [URL], Surface rheological analyses of polymeric solids were presented on the basis of scanning viscoelasticity microscopy (SVM) and lateral force microscopy (LFM). SVM observation for phase-separated polymer blend films revealed two-dimensional distribution of elasticity. In order to study surface thermal molecular motion of monodisperse polystyrene (PS), SVM and LFM measurements were made at various temperatures. Glass transition temperature, Tg, at the surface was discerned to be markedly lower than the corresponding bulk Tg, and the discrepancy of Tg between surface and bulk became larger with decreasing molecular weight. Such an intensive activation of thermal molecular motion at the PS surface can be explained in terms of an excess free volume induced by the segregated chain ends and a reduced cooperativity at the surface. Bulk Tg of miscible binary blends can be well expressed by the Gordon-Taylor equation. Extending this notion to surface, the surface composition in blends would be obtained by measuring surface Tg of each constituent as well as their blend. The surface composition in blend films of two PSs with different molecular weights was experimentally and systematically elucidated. The surface enrichment of a smaller molecular weight component became more remarkable with increasing molecular weight disparity between the two components due probably to an entropic effect..
256. Tisato Kajiyama, Daisuke Kawaguchi, Keiji Tanaka, Polymer chain diffusion at a temperature below its bulk glass transition temperature, Chinese Journal of Polymer Science (English Edition), 21, 2, 141-146, 2003.03, In this study, it was examined whether the dynamics of polymer chains at a surface is different from that in the bulk, and if so, to what extent they differ in terms of surface glass transition temperature and diffusion coefficient. Obtained results clearly indicate that surface chains can travel for a relatively large distance in comparison with the characteristic length scale of usual segmental motion even at a temperature below its bulk glass transition temperature, Tg
b. This is consistent with our previous results that the surface glass transition temperature is much lower than the corresponding Tg
b. Also, it was experimentally revealed that there was a gradient of molecular motion in the surface region..
257. Tisato Kajiyama, Keiji Tanaka, Atsushi Takahara, Surface thermal molecular motion of chain end-modified polystyrenes, Macromolecular Symposia, 10.1002/masy.200390036, 192, 265-270, 2003.03, [URL], Surface glass transition temperature, Tg
s, of three classes of monodisperse polystyrene, proton-terminated (PS-H), α,ω-diamino-terminated (α,ω-PS(NH2)2) and (α,ω-dicarboxy-terminated (α,ω-PS(COOH)2), were studied by scanning force microscopy. Tg
s of all samples was discernibly lower than the corresponding bulk glass transition temperature, Tg
b. Also, Tg
s value was strongly dependent on what the chemical structure of chain end groups was. Based on the time-temperature superposition principle, apparent activation energy of the αarelaxation process corresponding to surface segmental motion was evaluated to be approximately 230 kJ•mol-1. This value was much smaller than the reported bulk ones, and was independent of the chemical structure of chain ends. This result implies that the cooperativity for the αa-relaxation process at the PS surface is reduced in comparison with the bulk due probably to an existence of the free space presented to polymer segments at the surface. Hence, it was concluded that the surface αa-relaxation process was activated by not only the chain end effect but also the reduced cooperativity at the surface..
258. K.Tanaka, S.Dai, T.Kajiyama, K.Aoi, M.Okada, Aggregation States and Molecular Motion in Amphiphilic Poly(amido amine) Dendrimer Monolayers on Solid Substrates, Langmuir, 10.1021/la0261592, 19, 4, 1196-1202, 19 (4): 1196-1202, 2003.02.
259. D.Kawaguchi, K.Tanaka, T.Kajiyama, A.Takahara, S.Tasaki, Mobility Gradient in Surface Region of Monodisperse Polystyrene Films, Macromolecules, 10.1021/ma025667f, 36, 4, 1235-1240, 36 (4): 1235-1240, 2003.02.
260. K.Tanaka, K.Kojio, R.Kimura, A.Takahara, T.Kajiyama, Surface Relaxation Process of Poly(methyl methacrylate) Brushes Prepared by Atom Transfer Radical Polymerization, Polymer J., 10.1295/polymj.35.44, 35, 1, 44-49, 35:44-49, 2003.01.
261. A.Takahara, D.Kawaguchi, K.Tanaka, M.Tozu, T.Hoshi, T.Kajiyama, Analysis of Surface Composition of Isotopic Polymer Blends Based on Time-of-Flight Secondary Ion Mass Spectroscopy, Appl. Surf. Sci., 10.1016/S0169-4332(02)00748-1, 203, 538-540, 203-204:538-540, 2003.01.
262. T.Kajiyama, D.Kawaguchi, K.Tanaka, Polymer Chain Diffusion at a Temperature below Its Bulk Glass Transition Temperature, Chinese J. Polym. Sci., 21, 2, 141-146, 21:141-146, 2003.01.
263. K.Tanaka, D.Kawaguchi, Y.Yokoe, T.Kajiyama, A.Takahara, S.Tasaki, Surface Segregation of Chain Ends in alpha,omega-Fluoroalkyl-Terminated Polystyrenes Films, Polymer, 10.1016/S0032-3861(03)00391-4, 44, 15, 4171-4177, 44:4171-4177, 2003.01.
264. K. Tanaka, T. Kajiyama, A. Takahara, S. Tasaki, A novel method to examine surface composition in mixtures of chemically identical two polymers with different molecular weights, Macromolecules, 10.1021/ma011960o, 35, 12, 4702-4706, 35 (12): 4702-4706, 2002.06.
265. Keiji Tanaka, Hyuk Yu, Lipase activity on lipid/polymer binary monolayers
Lateral diffusion-controlled enzyme kinetics, Langmuir, 10.1021/la010965b, 18, 3, 797-804, 2002.02, [URL], This is a follow-up study to our recent reports of lipase catalysis on uniphasic binary monolayers of L-α-dilauroylphosphatidylcholine (DLPC) and cholesterol. The earlier studies were undertaken to show that the reaction kinetics on monolayers of ester hydrolysis catalyzed by an interface active enzyme, lipase, is closely correlated to the lateral dynamics, i.e., the hydrolysis of a lipase substrate is a diffusion-controlled process, whereby the rates were quantitatively analyzed in terms of a theory of purely two-dimensional diffusion-controlled reactions. In so establishing, cholesterol was used as the second component to retard the lateral diffusion coefficient of DLPC to different extents. On the other hand, phospholipids and cholesterol are being found to form "condensed complexes" even in homogeneous monolayers, hence the finding of the diffusion-controlled processes might well be construed to be unique to the phospholipid-cholesterol system. To show that the diffusion-controlled reaction kinetics on monolayers is of more general validity, i.e., not system-specific, we chose a completely different second component to constitute a binary homogeneous monolayer system by which we can vary the lipid diffusion coefficient. The second component is a synthetic polymer, poly(tert-butyl methacrylate) (PtBMA), well-known for its surface activity on the air/water interface, and is demonstrated to form uniphasic monolayers with DLPC at the air/aqueous buffer (pH 7) interface. Upon completing the entire set of measurements for the diffusion coefficients and the hydrolysis rates with the same substrate, umbelliferone stearate, we reached the conclusions that what we found with DLPC/ cholesterol are not unique to the system but equally applicable to DLPC/PtBMA, whereas the polymer is not likely to exert the same sort of retardation effect on monolayer dynamics by specific interactions that result in condensed complexes of phospholipid and cholesterol..
266. K.Tanaka, H.Yu, Lipase Activity on Lipid/Polymer Binary Monolayers: Lateral Diffusion-Controlled Enzyme Kinetics, Langmuir, 18:797-804, 2002.01.
267. F.Xie, H.F.Zhang, F.K.Lee, O.K.C.Tsui, Y.Yokoe, K.Tanaka, A.Takahara, T.Kajiyama, T.He, Effect of Low Surface Energy Chain Ends on the Glass Transition Temperature of Polymer Thin Films, Macromolecules, 10.1021/ma011689a, 35, 5, 1491-1492, 35:1491-1492, 2002.01.
268. H.-Q.Xiang, K.Tanaka, A.Takahara, T.Kajiyama, Spectroscopic and Electrochemical Characterizations of Dilithium Octacyanophthalocyanine Langmuir-Blodgett Films, Langmuir, 10.1021/la011401a, 18, 6, 2223-2228, 18:2223-2228, 2002.01.
269. A.Sakai, K.Tanaka, T.Kajiyama, A.Takahara, Thermal Molecular Motion at Atactic Polypropylene Surfaces, Polymer, 10.1016/S0032-3861(02)00340-3, 43, 19, 5109-5115, 43:5109-5115, 2002.01.
270. H.-Q.Xiang, K.Tanaka, T.Kajiyama,, Gas-Sensing Properties of Dilithium Octacyanophthalocyanine Langmuir-Blodgett Films, Langmuir, 10.1021/la026161t, 18, 23, 9102-9105, 18:9102-9105, 2002.01.
271. N. Satomi, K. Tanaka, A. Takahara, T. Kajiyama, T. Ishizone, S. Nakahama, Surface molecular motion of monodisperse (alpha,omega-diamino-terminated and (alpha,omega)-dicarboxy-terminated polystyrenes, Macromolecules, 10.1021/ma010126w, 34, 25, 8761-8767, 34 (25): 8761-8767, 2001.12.
272. X.Jiang, C.Z.Yang, K.Tanaka, A.Takahara, T.Kajiyama, Effect of Chain End Group on Surface Glass Transition Temperature of Thin Polymer Film, Phys. Lett. A, 10.1016/S0375-9601(01)00150-5, 281, 5-6, 363-367, 281:363-367, 2001.01.
273. T.Kajiyama, R.Tominaga, K.Kojio, K.Tanaka, Structual Study of Crystal Transition from Hexagonal to Rectangular Phase of Lignoceric Acid Monolayers, Bull. Chem. Soc. Jpn., 10.1246/bcsj.74.765, 74, 4, 765-771, 74:765-771, 2001.01.
274. K.Kojio, K.Tanaka, A.Takahara, T.Kajiyama, Novel Method to Prepare Organosilane Monolayer on Solid Substrate, Bull. Chem. Soc. Jpn., 10.1246/bcsj.74.1397, 74, 8, 1397-1401, 74:1397-1401, 2001.01.
275. H.-Q.Xiang, K.Tanaka, A.Takahara, T.Kajiyama, Reversible Reduction and Reoxidation of Langmuir-Blodgett Films of Octacyanophthalocyanine Dilithium Complex, Chem. Lett., 10.1246/cl.2001.536, 6, 536-537, 536-537, 2001.01.
276. N.Satomi, K.Tanaka, A.Takahara, T.Kajiyama, Effect of Internal Bulk Phase on Surface Viscoelastic Properties by Scanning Probe Microscopy, Macromolecules, 10.1021/ma001831s, 34, 18, 6420-6423, 34:6420-6423, 2001.01.
277. D.Kawaguchi, K.Tanaka, A.Takahara, T.Kajiyama, Surface Mobile Layer of Polystyrene Film below Bulk Glass Transition Temperature, Macromolecules, 10.1021/ma010012k, 34, 18, 6164-6166, 34:6164-6166, 2001.01.
278. X.Jiang, K.Tanaka, A.Sakai, A.Takahara, T.Kajiyama, Surface Relaxation Behavior of Proton-and Perfluoroalkyl-Terminated Poly(2-vinyl pyridine) Films, Polymer, 10.1016/S0032-3861(01)00384-6, 42, 21, 8959-8964, 42:8959-8964, 2001.01.
279. Atsushi Takahara, Kensuke Nakamura, Keiji Tanaka, Tisato Kajiyama, Polymer battery R&D in the U.S., Macromolecular Symposia, 10.1002/1521-3900(200010)159:1<229::AID-MASY229>3.0.CO;2-O, 159, 229-245, 2000.12, [URL], Polymer electrolytes that have been developed for battery applications fall into two general classes, neat or "pure" polymer and plasticized or gel in which the polymer is combined with a conducting organic electrolyte. The polyethylene oxide (PEO) and its modifications are typical of the "pure" polymer electrolytes. They have poor conductivity at room temperatures, but at elevated temperatures, their conductivity is of the order of 10
-3
to 10
-4
S/cm. The PEO electrolytes have found application in the high temperature (>60°C) lithium metal anode battery systems. The high temperature necessary for good operation makes them unsuitable for use in small consumer appliances. The polymer electrolyte battery development activities have resulted in several high performance battery systems now just entering the market. Not all of the developments have resulted in commercial cell production. The commercialization activities of high performance lithium-ion (Li-Ion) batteries have been based on two general plastic polymer systems: poly-vinylidene difluoride-hexafluoropropylene copolymer (PVdF-HFP) and polyacrylates. The polymer cells are expected to have advantages in manufacturing, flexibility, thin cell formats and lightweight packaging. Important parameters in PVdF gel electrolyte performance include the electrolyte type (combination of organic carbonates), temperature, and HFP copolymer content. Li-Ion coin cells fabricated with a polyolefin separator with either liquid electrolyte or with the PVdF gel polymer electrolyte have equivalent performance..
280. K. Tanaka, A. Takahara, T. Kajiyama, Rheological analysis of surface relaxation process of monodisperse polystyrene films, Macromolecules, 10.1021/ma000406w, 33, 20, 7588-7593, 33 (20): 7588-7593, 2000.10.
281. Keiji Tanaka, Hyitk Yu, Polymer modulated, diffusion-controlled enzyme kinetics on monolayers, Quaternary International, 41, 2, 1809-1810, 2000.08, A study was carried out to examine the monolayer dynamics and the hydrolysis kinetics of umbelliferone stearate (UMB-C18) on binary monolayers composed of dilauroylphosphatidylcholine (DLPC) and another viscosifier, PtBMA. Results of this study were compared to previous results using a different viscosifier, cholesterol, of the lipid monolayer..
282. Tisato Kajiyama, Keiji Tanaka, Noriaki Satomi, Atsushi Takahara, Surface rheology of polymeric solids, Chinese Journal of Polymer Science (English Edition), 18, 3, 239-248, 2000.05, Surface molecular motions of amorphous polymeric solids have been directly measured on the basis of scanning viscoelasticity microscopic (SVM) and lateral force microscopic (LFM) measurements. SVM and LFM measurements were carried out for films of conventional monodisperse polystyrene (PS) with sec-butyl and proton-terminated end groups at room temperature. In the case of the number-average molecular weight, M
n
, less than ca. 4.0 × 10
4
, the surface was in a glass-rubber transition state even though the bulk glass transition temperature, T
g
was far above room temperature, meaning that the surface molecular motion was fairly active compared with that in the bulk. LFM measurements of the monodisperse PS films at various scanning rates and temperatures revealed that the time-temperature superposition was applicable to the surface mechanical relaxation behavior and also that the surface glass transition temperature, T
g
σ
, was depressed in comparison with the bulk one even though the magnitude of M
n
was fairly high at 1.40 × 10
5
. The surface molecular motion of monodisperse PS with various chain end groups was investigated on the basis of temperature-dependent scanning viscoelasticity microscopy (TDSVM). The T
g
σ
s for the PS films with M
n
of 4.9 × 10
3
to 1.45 × 10
6
measured by TDSVM were smaller than those for the bulk one, with corresponding M
n
s, and the T
g
σ
s for M
n
s smaller than ca. 4.0 × 10
4
were lower than room temperature (293 K). The active thermal molecular motion at the polymeric solid surface can be interpreted in terms of an excess free volume near the surface region induced by the surface localization of chain end groups. In the case of M
n
= ca. 5.0 × 10
4
, the T
g
σ
s for the α,ω-diamino-terminated PS (α,ω-PS(NH
2
)
2
) and α,ω-dicarboxy-terminated PS (α,ω-PS(COOH)
2
) films were higher than that of the PS film. The change of T
g
σ
for the PS film with various chain end groups can be explained in terms of the depth distribution of chain end groups at the surface region depending on the relative hydrophobicity..
283. Keiji Tanaka, Steven P. Mecca, Hyuk Yu, Lipase catalysis on monolayers at the air/water interface. 2. Diffusion-controlled kinetics on quasi-two-dimension, Langmuir, 10.1021/la990925w, 16, 6, 2672-2676, 2000.03, [URL], Homogeneous exoplasmic leaflets of biomembrane are mimicked by lipid monolayers at the air/water interface. The reaction rates of lipase (Pseudomonas cepacia) catalyzed hydrolysis of a substrate (umbelliferone stearate) on L-α-dilauroylphosphatidylcholine/cholesterol mixed monolayers at the air/water interface are examined as a function of cholesterol composition, which is to vary the dynamics of the system. Lateral mobility as a measure of dynamics of phospholipids and adsorbed lipase molecules are probed with the technique of fluorescence recovery after photobleaching. Upon correlating the lateral diffusion coefficients of a probe lipid and lipase with the interfacial hydrolysis kinetics, we show for the first time that the catalytic reactions on the monolayers are diffusion-controlled. Moreover, our results are in a quantitative agreement with the two-dimensional reaction dynamics theory of Torney and McConnell..
284. Keiji Tanaka, Patricia A. Manning, Hyuk Yu, Lipase catalysis on monolayers at the air/water interface. 1. Kinetic rate constants on quasi-two-dimension, Langmuir, 10.1021/la9909244, 16, 6, 2665-2671, 2000.03, [URL], Chemical reactions on a cell membrane surface are of pivotal importance for cellular functions such as intracellular signal transduction. Of the variety of membrane proteins, those imbedded in hemi-leaflets of bilayer membranes can be mimicked structurally and dynamically on monomolecular layers of phospholipids at the air/water interface. This is to report the kinetics of lipase (Pseudomonas cepacia) catalyzed hydrolysis of a substrate (umbelliferone stearate) on uniphasic L-α-dilauroylphosphatidylcholine monolayers at the air/water interface. A novel experimental protocol of the interfacial reaction is employed to probe the enzymatic kinetics. The kinetic rate constants on the monolayers are extracted from the substrate and the enzyme concentration dependences of the initial hydrolysis rate. The lipase on monolayers at the air/water interface is highly activated over that in bulk solution, and the turnover number of the lipase catalysis is strongly dependent on the surface pressure of monolayers..
285. T. Kajiyama, Keiji Tanaka, N. Satomi, Atsushi Takahara, Surface glass transition temperatures of monodisperse polystyrene films by scanning force microscopy, Science and Technology of Advanced Materials, 10.1016/S1468-6996(99)00005-4, 1, 1, 31-35, 2000.03, [URL], Surface molecular motion of monodisperse polystyrene (PS) films was examined by scanning viscoelasticity microscopy (SVM) in conjunction with lateral force microscopy (LFM). The dynamic storage modulus, E1, and loss tangent, tan δ, at a PS film surface with a smaller number-average molecular weight, Mn, than 40k were found to be smaller and larger than those for the bulk sample even at room temperature, meaning that the PS surface is in a glass-rubber transition state or a fully rubbery one at this temperature if the Mn, is small. In order to elucidate quantitatively how vigorous the molecular motion at the PS surface is, SVM and LFM measurements were made at various temperatures. The glass transition temperature, Tg, at the surface was discerned to be markedly lower than its bulk Tg, and the discrepancy of Tg between surface and bulk becomes larger with the decreasing Mn. Such an intensive activation of thermal molecular motion at the PS surfaces can be explained in terms of an excess free volume in the vicinity of the film surface induced by the preferential segregation of chain end groups..
286. K.Tanaka, P.A.Manning, H.Yu, Lipase Catalysis on Monolayers at the Air/Water Interface. 1.Kinetic Rate Constants on Quasi-Two-Dimension, Langmuir, 16:2665-2671, 2000.01.
287. K.Tanaka, S.P.Mecca, H.Yu, Lipase Catalysis on Monolayers at the Air/Water Interface. 2.Diffusion-Controlled Kinetics on Quasi-Two Dimension, Langmuir, 2672-2676, 2000.01.
288. N.Miki, K.Tanaka, A.Takahara, T.Kajiyama, Secondary Ion Mass Spectroscopic Analysis of Copper Migration at the Copper/Polyimide Interface, J.Vac.Sci.Technol.B, 10.1116/1.591191, 18, 1, 313-316, 18:313-316, 2000.01.
289. T.Kajiyama, K.Tanaka, N.Satomi, A.Takahara,, Surface Glass Transition Temperatures of Monodisperse Polystyrene Films by Scanning Force Microscopy, Sci.Tech.Adv.Mater., 1:31-35, 2000.01.
290. T.Kajiyama, K.Tanaka, N.Satomi, A.Takahara, Surface Rheology of Polymeric Solids, Chinese J.Polym.Sci., 18, 3, 239-248, 18:239-248, 2000.01.
291. T.Kajiyama, D.Kawaguchi, A.Sakai, N.Satomi, K.Tanaka, A.Takahara, Determination Factors on Surface Glass Transition Temperatures of Polymeric Solids, High Perform. Polym., 10.1088/0954-0083/12/4/314, 12, 4, 587-597, 12:587-597, 2000.01.
292. Tisato Kajiyama, Daisuke Kawaguchi, Noriaki Satomi, Keiji Tanaka, Atsushi Takahara, Surface glass transition behaviors of glassy polymers, Reports on Progress in Polymer Physics in Japan, 43, 311-330, 2000, Recent studies of thermal molecular motions at polymer surfaces are reviewed. Although many arguments have been still going on, many results support a consistent notion that surface molecular motion is much more vigorous than that in its interior bulk region. Finally, surface dynamics at temperature below its bulk glass transition is also reviewed..
293. Xiqun Jiang, Keiji Tanaka, Atsushi Takahara, Seiichi Nakahama, Tisato Kajiyama, Chain end group-induced surface ordering in poly(styrene-b-4-vinylpyridine) symmetric diblock copolymer films, Polymer Journal, 31, 11 pt 2, 1015-1020, 1999.12, The proton-terminated and fluoroalkyl-terminated poly(styrene-b-4-vinylpyridine) [P(St-b-4VP)] symmetric diblock copolymers were synthesized by a sequential anionic polymerization. The surface chemical composition, surface morphology and surface mechanical properties of the diblock copolymer thin films were investigated on the basis of the angular-dependent X-ray photoelectron spectroscopic (ADXPS) measurement and transmission electron microscopic (TEM) observations. The XPS results revealed that in the case of the proton-terminated P(St-b-4VP) film, the surface weight fraction of poly(4-vinyl pyridine)(P4VP) decreased dramatically after annealing above the glass transition temperature, Tg of P(St-b-4VP), resulting in the formation of polystyrene (PS) surface layer in order to minimize the interfacial free energy at air-polymer interface. Whereas, in the cases of the fluoroalkyl-terminated P(St-b-4VP) films [P(St-b-4VP)-C
2
C
F
X
where -C
2
C
F
X
shows fluoroalkyl end group], the surface weight fraction of P4VP decreased slightly and still was more than 30% even after the annealing treatment. TEM observation revealed that the lamellar structure was formed in all P(St-b-4VP). The surface order and orientation of lamellar structure were strongly influenced by the chain end group species. That is, in the case of the proton-terminated P(St-b-4VP) film, the lamellar structure was oriented parallel to the film surface and the outermost layer was composed of PS. On the other hand, in the case of P(St-b-4VP)-C
2
C
F
X
, the well-developed lamellae was tilted ca. 45 deg to the film surface and the alternating PS and P4VP layers were exposed to the air interface. These results indicate that the surface order and orientation of microphase-separated lamellar structure strongly depend on the chemical structure of the chain end group..
294. X.Jinang, K.Tanaka, A.Takahara, S.Nakahama, T.Kajiyama, Chain End Group-Induced Surface Ordering in Poly(stylene-b-4-vinylpyridine) Symmetric Diblock Copolymer Films, Polymer J., 10.1295/polymj.31.1015, 31, 11, 1015-1020, 31:1015-1020, 1999.01.
295. K.Tanaka, P.A.Manning, V.K.Lau, H.Yu, Lipid Lateral Diffusion in Dilauroylphosphatidylcholine/Cholesterol Mixed Monolayers at the Air/Water Interface, Langmuir, 15 (2): 600-606, 1999.01.
296. Tisato Kajiyama, Noriaki Satomi, Keiji Tanaka, Atsushi Takahara, Surface, thermal and mechanical characteristics of polymeric solids, Macromolecular Symposia, 10.1002/masy.19991430114, 143, 171-183, 1999.01, [URL], Surface molecular motions of amorphous polymeric solids have been directly measured on the basis of lateral force microscopic (LFM) and scanning viscoelasticity microscopic (SVM) measurements. SVM measurement revealed that the molecular motion at the surface of the monodisperse polystyrene (PS) film with Mn less than ca.30k was fairly activated compared with that in a bulk region, mainly due to the surface segregation of chain end groups. Tempereature dependent LFM and SVM measurement revealed that the surface glass transition temperature, Tg of the monodisperse PS film was lower than the bulk one, even though Mn was fairly large as 140k and also, that the time-temperature superposition was applicable to the surface relaxation process. The chain end group segregation at the air/PS interface was verified from the dynamic secondary ion mass spectroscopic (DSIM S) depth profiling of the proton and deuterium ion for the end-labeled deutrated-PS (dPS) film. These results suggest that the surface Tg is depressed due to an increase in free volume near surface region, being induced by the preferential surface localization of chain end groups..
297. Keiji Tanaka, Patricia A. Manning, Victor K. Lau, Hyuk Yu, Lipid Lateral Diffusion in Dilauroylphosphatidylcholine/Cholesterol Mixed Monolavers at the Air/Water Interface, Langmuir, 15, 2, 600-606, 1999, Binary monolayers of L-α-dilauroylphosphatidylcholine (DLPC) and cholesterol were formed at the air/water interface by the successive addition method with chloroform as the spreading solvent at 296 K. Translational diffusion of a probe lipid in the monolayers as a function of cholesterol fraction was examined by the technique of fluorescence recovery after photobleaching in conjunction with epifluorescence microscopy and the Wilhelmy plate method. A transition from biphasic morphology to a visually homogeneous uniphasic monolayer occurred at surface pressures between 13 and 20 mN·m -1, depending on the cholesterol fraction in the monolayer. The lateral diffusion coefficient was found to decrease when surface pressure and/or cholesterol fraction were/was increased. The diffusion coefficients of the probe lipid in the homogeneous monolayers were analyzed on the basis of the free area model. The observed retardation of the diffusion is ascribed to an increase in the in-plane surface viscosity of monolayers. In the case of biphasic binary monolayers, the retardation with increasing cholesterol fraction is attributed to the obstacle mediated diffusion as in the effective medium analysis as well as to increasing surface viscosity..
298. Atsushi Takahara, X. Jiang, N. Satomi, Keiji Tanaka, T. Kajiyama, Analysis of surface mechanical properties of polymer blend ultrathin films by scanning force microscopy, Key Engineering Materials, 137, 79-86, 1998.12, Scanning viscoelasticity microscopy (SVM) is used in studies of the surface mechanical properties of polymeric solids. It was revealed that the surface molecular motion is fairly different from bulk one due to the surface segregation of chain end groups. The two-dimensional mapping of the surface mechanical properties for the polymer blend ultrathin films was carried out on nanometer scale..
299. K.Tanaka, A.Takahara, T.Kajiyama, Surface Molecular Aggregation Structure and Surface Molecular Motions of High-Molecular-Weight Polystyrene/Low-Molecular-Weight Poly(methyl methacrylate) Blend Films, Macromolecules, 10.1021/ma9709866, 31, 3, 863-869, 31 (3): 863-869, 1998.02.
300. X.Jiang, K.Tanaka, A.Takahara, T.Kajiyama, Effect of Chain End Group Hydrophobicity on Surface Aggregation Structure of Poly(stylene-block-4-vinylpyridine) Symmetric Diblock Copolymer Films, Polymer, 10.1016/S0032-3861(97)00567-3, 39, 12, 2615-2620, 39 :2615-2620, 1998.01.
301. T.Kajiyama, K.Tanaka, A.Takahara, Surface Segregation of the Higher Surface Free Energy Component in Symmetric Polymer Blend Films, Macromolecules, 10.1021/ma971247s, 31, 11, 3746-3749, 31 :3746-3749, 1998.01.
302. K.Tanaka, X.Jiang, K.Nakamura, A.Takahara, T.Kajiyama, T.Ishizone, A.Hirao, S.Nakahama, Effect of Chain End Chemistry on Surface Molecular Motion of Polystyrene Films, Macromolecules, 10.1021/ma9712561, 31, 15, 5148-5149, 31 :5148-5149, 1998.01.
303. T.Kajiyama, K.Tanaka, N.Satomi, A.Takahara, Surface Relaxation Process of Monodisperse Polystyrene Film Based on Lateral Force Microscopic Measurements, Macromolecules, 10.1021/ma971274i, 31, 15, 5150-5151, 31 :5150-5151, 1998.01.
304. A.Takahara, X.Jiang, N.Satomi, K.Tanaka, T.Kajiyama, Analysis of Surface Mechanical Properties of Polymer Blend Ultrathin Films by Scanning Force Microscopy, Key Eng. Mater., 137, 79-86, 137:79-86, 1998.01.
305. T.Kajiyama, K.Tanaka, A.Takahara, Study of the Surface Glass Transition Behavior of Amorphous Polymer Film by Scanning-Force Microscopy and Surface Spectroscopy, Polymer, 10.1016/S0032-3861(98)00049-4, 39, 19, 4665-4673, 39:4665-4673, 1998.01.
306. T.Kajiyama, K.Tanaka, A.Takahara, Surface Molecular Motion of the Monodisperse Polystyrene Films, Macromolecules, 10.1021/ma960582y, 30, 2, 280-285, 30 :280-285, 1997.01.
307. K.Tanaka, A.Takahara, T.Kajiyama, Effect of Polydispersity on Surface Molecular Motion of Polystyrene Films, Macromolecules, 10.1021/ma970057e, 30, 21, 6626-6632, 30 :6626-6632, 1997.01.
308. W.-K.Lee, J.-S.Yoon, K.Tanaka, N.Satomi, X.Jiang, A.Takahara, C.-S.Ha, T.Kajiyama, Relationships between Lateral Force Microscopy, Polym. Bull., 39 :369-376, 1997.01.
309. W.-K.Lee, K.Tanaka, A.Takahara, T.Kajiyama, C.-S.Ha, Surface Structure of Blend Films of Styrene/Acrylonitrile Copolymer and Poly(methyl methacrylate) (PMMA) or Hydrolyzed PMMA, Bull. Korean Chem. Soc., 18, 9, 958-961, 18 :958-961, 1997.01.
310. T.Kajiyama, K.Tanaka, A.Takahara, Surface Molecular Motion of Amorphous Polymeric Solids, Bull. Chem. Soc. Jpn., 10.1246/bcsj.70.1491, 70, 7, 1491-1503, 70 :1491-1503, 1997.01.
311. T.Kajiyama, K.Tanaka, A.Takahara, Analysis of Surface Molecular Motion of Amorphous Polymeric Solids on the Basis of Scanning Force Microscopy and X-ray Photoelectron Spectrocopy, Peoc. Japan Acad. B, 73 :132-137, 1997.01.
312. Tisato Kajiyama, Keiji Tanaka, Atsushi Takahara, Analysis of surface molecular motion of amorphous polymeric solids on the basis of scanning force microscopy and X-ray photoelectron spectroscopy, Proceedings of the Japan Academy Series B: Physical and Biological Sciences, 10.2183/pjab.73.132, 73, 7, 132-137, 1997.01, [URL], Surface molecular motions of amorphous polymeric solids have been directly measured on the basis of lateral force microscopic (LFM), scanning viscoelasticity microscopic (SVM) and differential X-ray photoelectron spectroscopic (D-XPS) studies. SVM and LFM measurements of monodisperse polystyrene (PS) films revealed that, in the case of the number-average molecular weight, Mn less than ca. 30k, the surface was in a glass-rubber transition state at room temperature even though the bulk glass transition temperature, Tg was far above room temperature. The active molecular motion at the polymeric solid surface can be interpreted mainly in terms of excess free volume near the surface region induced by the surface segregation of chain end groups, which was confirmed by dynamic secondary ion mass spectroscopy (DSIMS). D-XPS measurement revealed that the surface Tg for the poly(styrene-block-methyl methacrylate) diblock copolymer films increased gradually with an increase in depth from the air/polymer interface..
313. Won Ki Lee, Jeong Sik Yoon, Keiji Tanaka, Noriaki Satomi, Xiqun Jiang, Atsushi Takahara, Chang Sik Ha, Tisato Kajiyama, Relationships between lateral force and viscoelastic properties for amorphous polymer films based on lateral force microscopy, Polymer Bulletin, 10.1007/s002890050161, 39, 3, 369-376, 1997.01, [URL], The relationships between lateral force and viscoelastic properties of amorphous polymer surfaces with Tg's lower and higher than room temperature (295 K, RT) and their blend systems have been studied on the basis of lateral force microscopic (LFM) measurement. Under the conditions of scanning rate of 10
2
-10
5
nm sec
-1
, normal load of 5 nN and RT, the lateral forces of poly(methyl methacrylate) (PMMA) and polyisoprene (PI) homopolymers with Tg's fairly higher and lower than RT, respectively, did not depend on the scanning rate. Whereas, the lateral force of poly(methyl acrylate) (PMA) with Tg≤RT decreased with an increase in the scanning rate. Also, poly(vinyl acetate) (PVAc) with Tg≥RT showed slight dependence on the scanning rate. The scanning rate dependence of lateral force was similar to the frequency dependence of mechanical loss modulus. The results indicate that the magnitude of lateral force strongly depends on the state of thermal molecular motion. The lateral force-viscoelastic properties of miscible polymer blends was also investigated by LFM..
314. Tisato Kajiyama, Keiji Tanaka, Atsushi Takahara, Surface thermomechanical and glass transition temperature measurements of polymeric solids, Macromolecular Symposia, 10.1002/masy.19971180187, 118, 677-682, 1997.01, [URL], The surface molecular motion of polymeric solids was investigated on the basis of scanning force microscopic and temperature-dependent X-ray photoelectron spectroscopic measurements. The surface of the monodisperse polystyrene films was in a glass-rubber transition state even at 293 K in the case of number-average molecular weight less than ca. 30k. The surface glass transition temperature, Tgs for the symmetric poly(styrene-block-methyl methacrylate) diblock copolymer films were much lower than those for the bulk samples. A remarkable depression of Tg at the air-polymer interface was explained by the surface localization of chain end groups..
315. Won Ki Lee, Keiji Tanaka, Atsushi Takahara, T. Kajiyama, Chang Sik Ha, Surface Structure of Blend Films of Styrene/Acrylonitrile Copolymer and Poly(methyl methacrylate)(PMMA) or Hydrolyzed PMMA, Bulletin of the Korean Chemical Society, 18, 9, 958-961, 1997, The compatibility and the surface structure of blends of poly(styrene-co-acrylonitrile) (SAN) with either poly (methyl methacrylate) (PMMA) or hydrolyzed PMMA (H-PMMA) were studied in terms of film thickness, interaction, and surface free energy difference on the basis of X-ray photoelectron spectroscopy (XPS), attenuated total reflection Fourier transform IR spectroscopy and atomic force microscopy. The. XPS measurement showed that the surface enrichment of (PMMA/SAN) blends with different AN contents of SAN and with different carboxyl acid contents of PMMA was dependent on the molecular interaction, the surface free energy difference between components and the sample preparation history. It was found that the compatibility of H-PMMA and SAN was reduced with increasing carboxyl acid content of PMMA..
316. Atsushi Takahara, Keiji Tanaka, Shou Ren Ge, Tisato Kajiyama, Scanning force microscopic study of morphology and properties of multiphase polymer surface, Unknown Journal, 37, 2, 589-590, 1996.08.
317. K.Tanaka, A.Taura, S.-R.Ge, A.Takahara, T.Kajiyama, Molecular Weight Dependence of Surface Dymamic Viscoelastic Properties for the Monodisperse Polystyrene Film, Macromolecules, 10.1021/ma951378y, 29, 8, 3040-3042, 29 :3040-3042, 1996.01.
318. K.Tanaka, A.Takahara, T.Kajiyama, Film Thickness Dependence of Surface Structure of Immiscible Polystyrene/Poly(methyl methacrylate) Blends, Macromolecules, 10.1021/ma951140+, 29, 9, 3232-3239, 29 :3232-3239, 1996.01.
319. 田中敬二、高原 淳、梶山千里, 高分子固体膜表面の分子運動特性, 高分子論文集, 53 :582-591, 1996.01.
320. T. Kajiyama, Keiji Tanaka, S. R. Ge, Atsushi Takahara, Morphology and mechanical properties of polymer surfaces via scanning force microscopy, Progress in Surface Science, 10.1016/0079-6816(96)00006-8, 52, 1, 1-52, 1996.01, [URL], Scanning force microscopy is used in studies of the surface morphology and surface mechanical properties of polymeric solids. Several examples are presented to illustrate that SFM is a powerful and promising tool for investigations, such as, polyethylene single crystal, polymer blend thin films and polymerized organosilane monolayers. The imaging of nano-mechanical properties, such as, lateral force and elastic modulus of phase-separated polymer surfaces by SFM is presented. The application of SFM to the quantitative evaluation of surface viscoelasticity is also summarized..
321. Keiji Tanaka, Atsushi Takahara, Tisato Kajiyama, Surface molecular motion of polymeric solid films, KOBUNSHI RONBUNSHU, 10.1295/koron.53.582, 53, 10, 582-591, 1996.01, [URL], Surface dynamic storage modulus, E′, and surface loss tangent, tan δ, of monodisperse polystyrene (PS) films with various molecular weights were evaluated at 293 K on the basis of scanning viscoelasticity microscope (SVM) which was designed by the authors. In the case of the PS film with a number-average molecular weight, Mn, lower than ca. 30 k, the magnitudes of surface E′ and surface tan δ were smaller and larger than the magnitudes showing a glassy state, respectively. Thus, it seems reasonable to conclude that the PS film surface with Mn less than ca. 30 k is in a glass-rubber transition state even at 293 K. The scanning rate dependence of lateral force for the monodisperse PS films was investigated at 293 K by lateral force microscopy (LFM). Since the magnitude of lateral force was apparently dependent on the scanning rate, especially in the case of Mn lower than ca. 40 k, it seems reasonable to conclude that the PS film surface with Mn less than ca. 40 k is in a glass-rubber transition state at 293 K. The LFM results agreed well with the SVM results if the scanning rate of cantilever tip for LFM measurements corresponded to the measuring frequency for SVM measurements. The depth dependence of surface glass transition temperature, Tg, of the poly-(styrene-block-methyl methacrylate) diblock copolymer film was also investigated on the basis of the combination of temperature-dependent and angular-dependent X-ray photoelectron spectroscopic (TDXPS and ADXPS) measurements. It was revealed that Tg at the film surface was much lower than that of the bulk sample and its magnitude increased with the depth from the free surface. The remarkable depression of Tg at the polymeric surface was explained by the excess free volume induced due to the surface localization of chain end groups. The surface enrichment of chain end groups was confirmed by dynamic secondary ion mass spectroscopic measurement..
322. K.Tanaka, J.-S.Yoon, A.Takahara, T.Kajiyama, Ultrathinning-Induced Surface Phase Separation of Polystyrene/Poly(vinyl methyl ether) Blend Film, Macromolecules, 10.1021/ma00108a021, 28, 4, 934-938, 28 : 934-938, 1995.01.
323. T.Kajiyama, K.Tanaka, A.Takahara, Depth Dependence of the Surface Glass Transition Temperature of a Poly(styrene-block-methyl methacrylate) Diblock Copolymer Film on the Basis of Temperature-Dependent X-ray Photoelectron Spectroscopy, Macromolecules, 10.1021/ma00113a059, 28, 9, 3482-3484, 28 : 3482-3484, 1995.01.
324. K.Tanaka, A.Takahara, T.Kajiyama, Surface Molecular Motion in Thin Films of Poly(styrene-block-methyl methacrylate) Diblock Copolymer, Acta Polym., 10.1002/actp.1995.010460612, 46, 6, 476-482, 46 : 476-482, 1995.01.
325. T.Kajiyama, K.Tanaka, I.Ohki, S.-R.Ge, A.Takahara, Direct Observation of Surface Morphology and Surface Viscoelastic Properties of Polymeric Solids Based on Scanning Force Microscopy, Proc.Japan Acad. B, 10.2183/pjab.71.75, 71, 2, 75-80, 71 :75-80, 1995.01.
326. T.Kajiyama, K.Tanaka, I.Ohki, S.-R.Ge, J.-S.Yoon, A.Takahara, Imaging of Dynamic Viscoelastic Properties of a Phase-Separated Polymer Surface by Forced Oscillation Atomic Force Microscopy, Macromolecules, 10.1021/ma00104a061, 27, 26, 7932-7934, 27 :7932-7934, 1994.01.
327. M.Hino, M.Kitaguchi, H.Hayashida, Y.Kawabata, S.Tasaki, T.Ebisawa, D.Yamazaki, R.Maruyama, K.Tanaka, N.Torikai, R.Inoue, T.Kanaya, A Test of MIEZE-Reflectometer for study of surface and interface, Physica B, 印刷中.

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