Kyushu University Academic Staff Educational and Research Activities Database
List of Reports
Keiji Tanaka Last modified date:2021.06.23

Professor / Applied Fine Chemistry / Department of Applied Chemistry / Faculty of Engineering


Reports
1. 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, Vol.51, No.3, pp.359-363, 2019.03, © 2018, The Society of Polymer Science, Japan. 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.]..
2. 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, pp.861-880, 2015.09, 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..
3. Dong Ha Kim, Keiji Tanaka, Juan Peng, A Special Issue on Functional Polymeric Nanomaterials, SCIENCE OF ADVANCED MATERIALS, 10.1166/sam.2015.2274, Vol.7, No.5, pp.827-829, 2015.05.
4. An Effect of Mechanical Properties of Polymer Surface on Fibroblast Adhesion.
5. Aggregation States and Molecular Motion of Well-Defined Vinyl Polymers at the Water Interface.
6. Tomoyasu Hirai, Shota Osumi, Hirold Ogawa, Teruaki Hayakawa, Atsushi Takahara, Keiji Tanaka, Precise Synthesis and Surface Wettability of a Polymer with Liquid Crystalline Side Chains, MACROMOLECULES, 10.1021/ma5010265, Vol.47, No.15, pp.4901-4907, 2014.08, Well-defined poly(methacrylate)s with liquid crystal side chains, designated as PPHM, were synthesized by a living anionic polymerization method. Introducing a short-length alkyl chain at the end of the side chain, the solubility of the polymer was improved, resulting in higher molecular weight polymers. While the highest weight-average molecular weight (M-w) of PPHM was 68k, it exceeded 100k for a slight-polydisperse PPHM. Wide-angle X-ray diffraction (WAXD) revealed that PPHM formed a smectic A phase with 2.7 nm layer spacing and that the layer structure is present even in the glassy state at room temperature. Molecular aggregation states of PPHM in surface regions of films were characterized by sum-frequency generation, grazing-incidence WAXD, and contact angle measurements. The results show that the PPHM with a larger M-w formed a layer structure parallel to the film plane. Although low M-w PPHM also maintained a layer structure, the structure became more random within internal regions. The surface reorganization of PPHM with larger M-w was suppressed in comparison with smaller ones..
7. ATARASHI Hironori, HORI Ko‐ichiro, KAI Naoki, HORINOUCHI Ayanobu, FUJII Yoshihisa, HINO Masahiro, TANAKA Keiji, States of Poly(methyl methacrylate) Monolayers Supported on Substrates in Non-solvents, 日本原子力研究開発機構JAEA-Review(Web), No.2013-040, p.1-5-9 (WEB ONLY), 2014.02.
8. 環状ジスルフィドを用いた自己組織化単分子膜の作製とその表面摩擦特性.
9. 環状ジスルフィド自己組織化単分子膜の表面特性.
10. Molecular Aggregation States of Poly(meth)acrylate Thin Films in Non-solvents.
11. Molecular Aggregation States of Poly(meth)acrylate Thin Films in Non-solvents.
12. Rheological Analysis of Polymer Surfaces by Scanning Force Microscopy.
13. Discoloration Phenomenon Induced by the Combination of Phenolic Antioxidants and Hindered Amine Light Stabilizers
.
14. 水界面における高分子ブレンドの構造形成と生体不活性.
15. 水界面におけるポリメタクリル酸メチルの構造・物性に及ぼす立体規則性の効果.
16. 異種固体界面における高分子の凝集構造および緩和挙動.
17. 高分子電解質の水収着挙動に及ぼす薄膜化の効果.
18. Thermal Molecular Motion of Poly(methyl methacrylate) at Various Interfaces.
19. Masayuki Haraguchi, Tomoyasu Hirai, Masaaki Ozawa, Misao Miyamoto, Keiji Tanaka, "One-step Synthesis of Hyper-branched Polymer with Perfluoroalkyl Segments", KGK 7-8, 2012.07.
20. Aggregation State and Molecular Motion of Poly(methyl methacrylate) at the Water Interface.
21. XIV.接着の物理 接着の物理(7)水界面におけるポリメタクリル酸メチルの凝集状態と分子鎖熱運動特性.
22. 水界面におけるポリスチレン膜の分子鎖凝集構造.
23. 高分子電解質薄膜の含水挙動に及ぼす界面効果.
24. HORINOUCHI Ayanobu, FUJII Yoshihisa, TANAKA Keiji, An Effect of Stereoregularity on Aggregation States of Poly(methyl methacrylate) at Water Interface, 高分子学会予稿集(CD-ROM), Vol.61, No.1, p.ROMBUNNO.2L16, 2012.05.
25. IKINAGA Yukari, TSURUTA Hirofumi, FUJII Yoshihisa, TANAKA Keiji, Construction of Polymer Films with a Stiff Surface Layer Consist of Inorganic Network, 高分子学会予稿集(CD-ROM), Vol.61, No.1, p.ROMBUNNO.1L26, 2012.05.
26. ZHANG Cui, FUJII Yoshihisa, TANAKA Keiji, Effect of Long Range Interaction on Thermal Molecular Motion of Polystyrene Thin Films, 高分子学会予稿集(CD-ROM), Vol.61, No.1, p.ROMBUNNO.2L14, 2012.05.
27. TSURUTA Hirofumi, FUJII Yoshihisa, KATAOKA Hiroshi, ISHIZONE Takashi, TANAKA Keiji, Surface and Interfacial Aggregation States of Monodisperse Polystyrene Terminated with Adamantyl Groups, 高分子学会予稿集(CD-ROM), Vol.61, No.1, p.ROMBUNNO.2L15, 2012.05.
28. 界面 固体界面における分子鎖熱運動特性.
29. Evaluation of Resistance of Fluoroelastomer to Ozone in Water.
30. FUJII Yoshihisa, ATARASHI Hironori, TANAKA Keiji, NAGAMURA Toshihiko, HINO Masahiro, Analysis of Adsorption Behavior for Proteins onto (Liquid/Polymer) Interface, 日本原子力研究開発機構JAEA-Review(Web), No.2011-050, p.1-5-24 (WEB ONLY), 2012.03.
31. ANNAKA Masahiko, FUJII Yoshihisa, ATARASHI Hironori, TANAKA Keiji, NAGAMURA Toshihiko, HINO Masahiro, Effects of Molecular Weight and Surface Density on Conformation of Poly(N-isopropylacrylamide) Brushes Immobilized Onto A Substrate, 日本原子力研究開発機構JAEA-Review(Web), No.2011-050, p.1-5-23 (WEB ONLY), 2012.03.
32. 側鎖型誘起キラル高分子の膜凝集状態.
33. 濃縮現象を用いたゴム表面の改質.
34. 高分子電解質薄膜の凝集構造に及ぼす表面・界面の効果.
35. Analysis of Swelling Behavior for Soft Nano-films by Optical Reflectivity.
36. Density Distributions of Poly(methyl methacrylate) Thin Films in Non-solvents.
37. 側鎖型誘起キラル高分子膜の表面特性.
38. 水界面における立体規則性ポリメタクリル酸メチルの凝集状態.
39. 濃縮現象を用いた耐酸化高分子表面の構築.
40. 表面濃縮現象を利用した耐候性高分子膜の構築.
41. 高分子電解質膜の凝集構造とその膜厚依存性.
42. Atsuomi Shundo, Keiko Mizuguchi, Misao Miyamoto, Masahiro Goto, Keiji Tanaka, Controllable heterogeneity in a supramolecular hydrogel, Chemical Communications, 10.1039/c1cc12733k, Vol.47, No.31, pp.8844-8846, 2011.08, A dispersion of a peptide amphiphile into water forms hierarchical fibril structures, leading to a supramolecular hydrogel. We here report that there exists dynamic heterogeneity in the gel, which might be induced by the heterogeneous fibril network. The network, and therefore, the heterogeneity, can be easily regulated by changing the temperatures used to dissolve the gelator in water. © 2011 The Royal Society of Chemistry..
43. 走査プローブ顕微鏡を使いこなす 4 液中走査フォース顕微鏡(SFM)で高分子界面物性を測る.
44. 超薄膜中における分子鎖凝集状態.
45. ポリメタクリル酸メチル膜への非溶媒収着とその膜厚依存性.
46. 和周波発生分光測定に基づく(ポリメタクリル酸メチル/水)界面のナノ構造:スピンコート膜と濃厚ブラシの比較.
47. 基板界面における分子鎖の凝集状態と熱運動性の関係.
48. 異種固体材料界面における高分子鎖の凝集状態と熱運動特性.
49. 非溶媒界面における高分子の凝集状態と熱運動特性.
50. 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, Vol.257, No.3, pp.1145-1148, 2010.11, 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. (C) 2010 Elsevier B.V. All rights reserved..
51. ポリメタクリル酸メチル膜表面の環境変化に伴う凝集構造変化.
52. 高分子電解質膜のプロトン伝導における膜厚の効果.
53. ソフトマター研究の最前線 異種固体界面における高分子の熱運動特性.
54. ポリメタクリル酸メチルナノファイバーマットの動的粘弾性測定.
55. KAI Naoki, FUJII Yoshihisa, TANAKA Keiji, Local Conformation of Polystyrene on Solid Interface and its Temperature Dependence, 高分子学会予稿集(CD-ROM), Vol.59, No.1 Disk1, p.ROMBUNNO.2L10, 2010.05.
56. 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, Vol.1, No.3, pp.303-311, 2010.05, The local conformation of poly(methyl methacrylate) (PM MA) chains at the nitrogen (N-2) 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 N-2 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 a methyl, ester methyl and methylene groups were present. While the a 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 N-2 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 a 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..
57. 水環境下におけるポリメタクリル酸メチル薄膜の凝集構造.
58. 電界紡糸ポリメタクリル酸メチルの分子鎖熱運動性.
59. 非溶媒界面を利用した高分子微粒子の機能化.
60. 高分子電解質薄膜のプロトン伝導.
61. Yoshihisa Fujii, Toshihiko Nagamura, Keiji Tanaka, Relaxation Behavior of Poly(methyl methacrylate) at a Water Interface, JOURNAL OF PHYSICAL CHEMISTRY B, 10.1021/jp909373g, Vol.114, No.10, pp.3457-3460, 2010.03, The relaxation behavior of poly(methyl methacrylate) (PMMA), spin-coated oil 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 alpha(a)-relaxation process was Much smaller than those for the original alpha(a)-relaxation processes at the intact surface and in the bulk. The depth profile of the glass transition temperature (T-g) of the PMMA film in water was obtained, showing that T-g decreases with proximity to the water phase, The T-g. depression observed here was best explained in terms of the water Content of the film, rather than a confinement effect..
62. SPMを用いた高分子表面の力学物性評価.
63. 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, Vol.1, No.5, pp.881-885, 2010.03, 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 chi 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..
64. 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, Vol.50, No.20, pp.4868-4875, 2009.09, Hyper-branched polystyrenes (HBPS) were synthesized. The bulk glass transition temperature (T-g) measured by differential scanning calorimetry (DSC) for two kinds of HBPS with an equivalent M-w, 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 T-g 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. (C) 2009 Elsevier Ltd. All rights reserved..
65. K. Tanaka, Interfacial Characterization of Poly(methyl methacrylate) in Water, 高分子 58(1), 2009.06.
66. 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, Vol.113, No.14, pp.4571-4577, 2009.04, 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 (T(g)) was discernibly higher at the interface than in the internal bulk region. Measurements at different incident angles of excitation pulses revealed that T(g) 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 T(g) value at the interface decreased with decreasing molecular weight. However, the decrement for the interfacial T(g) was not as much as that for the bulk T(g), 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..
67. Polymer/Liquid Interface.
68. FUJII Yoshihisa, TANAKA Keiji, NAGAMURA Toshihiko, HINO Masaya, Analysis of Aggregation States in Ultrathin Polymer Blend Films Confined Between Solid Substrates, 日本原子力研究開発機構JAEA-Review, p.261, 2009.01.
69. 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, Vol.254, No.17, pp.5435-5438, 2008.06, 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. (c) 2008 Elsevier B.V. All rights reserved..
70. 水とポリメタクリル酸メチル膜界面の凝集構造と分子運動特性.
71. (ポリメタクリル酸メチル/水)界面の凝集構造評価.
72. 中性子反射率測定による高分子界面の構造・物性研究 水と接触したポリメタクリル酸メチルの界面キャラクタリゼーション.
73. Fumi Ariura, Keiji Tanaka, Toshihiko Nagamura, Redouane Borsali, Michel Schappacher, Alain Deffieux, POLY 415-Investigations of bulk properties of polystyrene combs, ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, Vol.235, 2008.04.
74. 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, Vol.37, No.3, pp.326-327, 2008.03, 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..
75. 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, Vol.254, No.10, pp.3180-3183, 2008.03, 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 mu m. 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. (c) 2007 Published by Elsevier B.V..
76. 高機能フィルムの開発,現状と展望 走査フォース顕微鏡による高分子薄膜の表面・内部の構造評価技術.
77. 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, Vol.24, No.1, pp.296-301, 2008.01, 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..
78. 高性能・高機能高分子デバイス構築のための界面デザイン.
79. ポリメタクリル酸メチルと貧溶媒との界面構造キャラクタリゼーション.
80. Hideki Sugihara, Kazuyuki Oya, Hiroki Murase, Keiji Tanaka, Keiichi Akabori, Tisato Kajiyama, Atsushi Takahara, POLY 628-Imaging of mechanical properties for surface and internal phase of multiphase polymer thin films, ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, Vol.234, 2007.08.
81. 中性子反射率測定による液体/高分子界面の構造評価.
82. 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, Vol.111, No.27, pp.7761-7766, 2007.07, 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 I-1 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 gamma and beta relaxation temperatures..
83. Hierarchical thermal molecular motion in thin polymer films
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..
84. 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, Vol.36, No.6, pp.808-809, 2007.06, 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..
85. 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, Vol.83, No.1, p.012023, 2007.06, 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. © 2007 IOP Publishing Ltd..
86. 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, Vol.23, No.13, pp.7269-7275, 2007.06, 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. alpha,omega-Fluoroalkyl- and alpha,omega-carboxy-terminated polystyrenes (alpha,omega-hPS(R(f))(2) and alpha,omega-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 alpha,omega-hPS(R(f))(2)/dPS blend film, alpha,omega-hPS(R(f))(2) was enriched at the surface owing to the surface localization of the R(f) 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 alpha,omega-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 alpha,omega-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 R(f) and COOH chain ends were partitioned to the substrate interface for the alpha,omega-hPS(R(f))(2)/dPS and alpha,omega-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..
87. 気体界面におけるポリメタクリル酸メチルの膨潤状態と分子鎖熱運動性.
88. 貧溶媒との界面における高分子の力学物性評価.
89. K. -I. Akabori, K. Tanaka, A. 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, Vol.141, pp.173-180, 2007.02, Mechanical relaxation behavior in ultrathin polystyrene (PS) films supported on silicon oxide (SiO(x)) 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, alpha(a)-relaxation process corresponding to the segmental motion did not show any deviation from the bulk behavior. In contrast, for the films thinner than about 50 nm, the relaxation time distribution for the alpha(a)-process became broader, probably due to a mobility gradient in the surface and interfacial regions. When we sandwiched an ultrathin PS film between SiO(x) layers, another relaxation process, in addition to the original alpha(a)-process, appeared at a higher temperature side that we assigned to the interfacial alpha(a)-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..
90. AOKI Takashi, OKAMOTO Yasushi, IZUMI Takao, KATO Kazuo, TANAKA Keiji, TAKAHARA Atsushi, KAJIYAMA Tisato, A Fundamental Study of Adhesive Reliability-A Study of PBT-Epoxy Adhesive Interface-, Rev Automot Eng, Vol.28, No.1, pp.73-79, 2007.01.
91. 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, Vol.44, No.24, pp.3598-3604, 2006.12, 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 (G(L)) was examined with a conventional lapshear measurement. G(L) 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 G(L) 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. (c) 2006 Wiley Periodicals, Inc..
92. 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, Vol.89, No.6, p.061916-1-2, 2006.08, 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 (T-g) was discernibly higher at the interface than in the bulk. Measurements at different incident angles of excitation pulses revealed that T-g became higher the closer to the interface. This is the observation for a T-g gradient of polymers at the interface. (c) 2006 American Institute of Physics..
93. 水界面におけるポリメタクリル酸メチルの凝集構造と分子鎖熱運動性.
94. Molecular aggregation structure of polyethylene thin films prepared on silicon substrates
In this study, structural features of crystalline polymers at the solid surface were analyzed by synchrotron grazing-incidence X-ray diffraction (SR-GIXD) measurements. Thin films of high-density polyethylene (HDPE) were prepared on silicon substrates from a p-xylene solution by a dip-coating method. The dip-coated films and the dip-coated and melt-crystallized ones were annealed at temperatures (Ta) of 373K-393K under N 2 atmosphere. The in-plane GIXD measurement for the HDPE thin films was carried out at the BL13XU of SPring-8, Japan. Bragg diffraction from the near-surface and the bulk of the films was detected at incident angles smaller and larger than the critical angle, respectively. Comparison of the surface-sensitive GIXD data with the bulk one revealed that the dimensions of orthorhombic unit cell in the near-surface region were smaller than those in the bulk region. This might relate to thermal stress induced between the HDPE film and the silicon substrate in film preparation..
95. 高分子加工の基礎研究 2. 評価技術の進歩―表面レオロジー.
96. 環状ポリスチレン薄膜の分子鎖熱運動性.
97. KAJIYAMA Tisato, TANAKA Keiji, TAKAHARA Atsushi, SASAKI Sono, Establishment of How to Analyze Molecular Motion for Polymer Chains at Surface and Interfaces, Annu Rep Fac Eng Kyushu Univ, Vol.2004, pp.10-17, 2005.05.
98. 環状ポリスチレン膜の表面緩和挙動.
99. A Sakai, K Tanaka, Y Fujii, T Nagamura, T Kajiyama, Structure and thermal molecular motion at surface of semi-crystalline isotactic polypropylene films (vol 46, pg 429, 2005), POLYMER, 10.1016/j.polymer.2004.12.036, Vol.46, No.5, p.1717, 2005.02.
100. K Tanaka, Y Tateishi, T Nagamura, Photoisomerization of azobenzene probes tagged to polystyrene in thin films, MACROMOLECULES, 10.1021/ma048579z, Vol.37, No.22, pp.8188-8190, 2004.11.
101. 空気および水界面におけるポリメタクリル酸メチルの分子運動特性.
102. TAKAHARA A, KAWAGUCHI D, TANAKA K, TASAKI S, KAJIYAMA T, Neutron Reflectivity Studies on Interfacial Composition in Blend Films of Polystyrene and Poly(vinyl methyl ether), 日本原子力研究所JAERI-Review, p.265, 2004.08.
103. TANAKA K, KAWAGUCHI D, TASAKI S, TAKAHARA A, KAJIYAMA T, Time Evolution of Interfacial Thickness in Polymer Bilayers below Its Bulk Glass Transition Temperature by Neutron Reflectivity, 日本原子力研究所JAERI-Review, p.264, 2004.08.
104. M Hikita, K Tanaka, T Nakamura, T Kajiyama, A Takahara, Aggregation states and surface wettability in films of poly(styrene-block-2-perfluorooctyl ethyl acrylate) diblock copolymers synthesized by atom transfer radical polymerization, LANGMUIR, 10.1021/la049556g, Vol.20, No.13, pp.5304-5310, 2004.06, Well-defined poly(styrene-block-2-perfluorooctyl ethyl acrylate) [P(St-b-PFA)] copolymers with various chemical compositions were synthesized by atom transfer radical polymerization. Films of P(St-b-PFA) were structurally characterized, from bulk to surface, on the basis of transmittance electron microscopic observation and small-angle X-ray scattering, X-ray photoelectron spectroscopic, and contact angle measurements. For a comparison, poly(styrene-random-2-perfluorooctyl ethyl acrylate) [P(St-ran-PFA)] copolymers were also synthesized by conventional free radical polymerization. While P(St-b-PFA) with the 2-perfluorooctyl ethyl acrylate (PFA) content higher than 18.7 mol % formed a typical phase-separated cylinder structure, P(St-b-PFA) with a lower PFA content and P(St-ran-PFA) were in a miscible state. Since the perfluoroalkyl groups possess extremely low surface energy, they were preferentially segregated at the film surface, resulting in the formation of the PFA surface layer. This was the case for all P(St-b-PFA) films examined, although the aggregation state at the surface was strongly dependent on the PFA content. In the case of the P(St-b-PFA) with the PFA content higher than 18.7 mol %, both advancing and receding contact angles for water were 120degrees and even larger with almost no hysteresis. In addition, extremely excellent oil-repellent surface properties such as advancing and receding contact angles for dodecane of 76degrees and 75degrees were also observed. However, these intriguing liquid-repellent properties were not observed for the films of miscible P(St-b-PFA) and P(St-ran-PFA). Therefore, it can be concluded that the internal structure beneath the surface as well as the surface itself should be deeply considered to design excellent and stable liquid-repellent materials..
105. ポリメタクリル酸メチル膜表面の分子運動特性に及ぼす立体規則性の影響.
106. N Hosaka, K Tanaka, H Otsuka, A Takahara, Dewetting behavior of polymer thin film with octacyclopentylsilsesquioxane nanofiller., ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, Vol.227, p.U834, 2004.03.
107. T Kajiyama, K Tanaka, A Takahara, Analysis of surface mobility in polystyrene films with monodisperse and bimodal molecular weights by lateral force microscopy, JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY, 10.1002/pola.10873, Vol.42, No.3, pp.639-647, 2004.02, The surface glass-transition temperature (T-g(s)) in monodisperse polystyrene (PS) films was examined on the basis of the temperature dependence of the lateral force at a given scanning rate. T-g(s) of the PS films was found to be markedly lower than the corresponding bulk glass-transition temperature over the entire molecular weight range (4900-1,460,000). Also, the apparent activation energy of the surface segmental motion in the PS films was 230 +/- 10 M mol(-1), significantly smaller than that for bulk PS. Finally, T-g(s) measurement by lateral force microscopy was applied to binary PS mixtures with different molecular weights. On the basis of the Gordon-Taylor equation, the surface composition of the shorter component in the blend films was successfully obtained. (C) 2003 Wiley Periodicals, Inc..
108. HIKITA M, TAKIZUKA N, TANAKA K, TAKAHARA A, KAJIYAMA T, Characterizations and Surface Wettability of Fluorinated Block Copolymers Synthesized by Atom Transfer Radical Polymerization, Trans Mater Res Soc Jpn, Vol.29, No.1, pp.225-228, 2004.02.
109. IZUMI T, NARITA R, TANAKA K, TAKAHARA A, KAJIYAMA T, Influence of annealing treatment on the Adhesion of Poly(butylene terephthalate) and its Interfacial structure, Trans Mater Res Soc Jpn, Vol.29, No.1, pp.229-232, 2004.02.
110. AKABORI K, TANAKA K, NAGAMURA T, TAKAHARA A, KAJIYAMA T, Segmental Motion in Polystyrene Thin and Ultrathin Films Based on Dynamic Viscoelastic Measurement, Trans Mater Res Soc Jpn, Vol.29, No.1, pp.217-220, 2004.02.
111. YOKOYAMA H, TANAKA K, TAKAHARA A, KAJIYAMA T, SUGIYAMA K, HIRAO A, Surface Segregation of Fluoroalkyl Side Group of Fluorinated Block Copolymers, Trans Mater Res Soc Jpn, Vol.29, No.1, pp.279-282, 2004.02.
112. H Yokoyama, K Tanaka, A Takahara, T Kajiyama, K Sugiyama, A Hirao, Surface structure of asymmetric fluorinated block copolymers, MACROMOLECULES, 10.1021/ma035191f, Vol.37, No.3, pp.939-945, 2004.02, Surface structures of asymmetric poly [styrene-block-4-(perfluorooctylpropyloxy)styrene] block copolymers (PS-PF) with the shorter PF block than the PS block have been investigated using X-ray photoelectron spectroscopy (XPS) and dynamic secondary ion mass spectrometry (SIMS). Fluorooctyl side groups (C8F17) of the block copolymers segregate to the surface due to their low surface energy. Asymmetry of the block remarkably influences the structure of the C8F17 side groups and the backbone of PS-PF copolymers at the surface. When a weight fraction of the PF block, f(PF)(wt), is 0.09, the surface is partially covered by the C8F17 side groups with a thickness thinner than the length of the C8F17 side group. The C8F17 side groups hence lie parallel to the surface. When f(PF)(wt) is approximately 0.25, the backbone of the PF block lies parallel to the surface, and the C8F17 side groups stand perpendicular to the surface. Such a conformation results in a domain thickness of the PF block comparable to the length of the C8F17 side group. However, as f(PF)(wt) goes beyond 0.3, the backbone of the PF block orients toward the surface while the top surface region, i.e., 1.5 nm from the surface, is still occupied by the C8F17 side groups standing perpendicular to the surface..
113. T.Kajiyama, K.Kojio, K.Tanaka, Aggregation States and Molecular Motion of Polymer Ultrathin Films Prepared at the Air/Water Interface, Colloid Interface Sci., 111,159-179, 2004.01.
114. 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, Vol.36, No.18, pp.6824-6830, 2003.09, Surface aggregation states in miscible blends of monodisperse polystyrene (PS) and poly(vinyl methyl ether) (PVME) were studied by X-ray photoelectron spectroscopy (XPS) in conjunction with neutron reflectivity (NR). In the case of symmetric blends in terms of degree of polymerization, N, PVME and PS were preferentially segregated at the film surface and the interface with a silicon wafer, respectively, to minimize free energy of the system. The concentration profile near the surface obtained by experiments was consistent with a mean-field prediction. Also, the surface composition in symmetric blends composed of PS terminated by fluoroalkyl groups at both ends (a,omega-PS(R-f)(2)) and PVME was examined. In this case, the surface enrichment of PVME was suppressed by virtue of the surface localization of fluoroalkyl end groups, and the composition was strongly dependent on N. The surface in asymmetric alpha,omega-PS(R-f)(2)/PVME blend, in which N of alpha,omega-PS(R-f)(2) was much smaller than that of PVME, was mostly covered with the PS segments. The results presented imply a possibility that the surface composition in miscible polymer mixtures could be perfectly regulated combining the chain end effect with the molecular weight disparity between the components..
115. ポリメタクリル酸メチル膜表面の凝集状態と分子鎖熱運動性.
116. 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, Vol.19, No.17, pp.6573-6575, 2003.08, A monodisperse polystyrene (PS) film was spin-coated on a silicon wafer with native oxide layer and was in part scratched by a blade. Then, the surface modulus on a given area, in which PS and bared silicon were present, was two-dimensionally mapped as a function of temperature by scanning viscoelasticity microscopy. We visually present evidence that the PS surface started to soften up at a temperature much lower than the bulk glass transition temperature..
117. K Akabori, K Tanaka, T Kajiyama, A Takahara, Anomalous surface relaxation process in polystyrene ultrathin films, MACROMOLECULES, 10.1021/ma034001y, Vol.36, No.13, pp.4937-4943, 2003.07, Monodisperse polystyrene (PS) films with various thicknesses were spun-coated on silicon wafers with native oxide layer. Surface relaxation behavior in the PS films was studied as a function of thickness by lateral force microscopy (LFM). In the case of a thick PS film, a clear lateral force peak corresponding to surface alpha(a)-relaxation process of segmental motion was observed at a temperature much lower than the bulk glass transition temperature, T-g. As the film became thinner than 3-4 times the radius of gyration of an unperturbed consistent chain, the peak on lateral force vs temperature curve started to broaden out with decreasing thickness and eventually split into two peaks. The appearance temperature of the surface a alpha(a)-relaxation peak was invariant with respect to the film thickness even in such an ultrathin state, meaning that surface T-g was insensitive to the thickness. On the other hand, the ultrathinning-induced relaxation process, called surface beta-relaxation, was strongly dependent on the thickness in terms of relaxation temperature and apparent activation energy. Finally, possible origins of the surface beta-relaxation process were proposed..
118. TAKAHARA A, KAWAGUCHI D, TANAKA K, TASAKI S, KAJIYAMA T, Chain End Distribution near the Surface in Polymer Films by Neutron Reflectivity., 日本原子力研究所JAERI-Review, p.253, 2003.07.
119. KAJIYAMA T, KAWAGUCHI D, TANAKA K, TASAKI S, TAKAHARA A, Molecular Weight Dependence of Interfacial Broadening at (Polystyrene/Deuterated Polystyrene) Bilayers below Bulk Glass Transition Temperature by Neutron Reflectivity., 日本原子力研究所JAERI-Review, p.252, 2003.07.
120. 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, Vol.44, No.15, pp.4171-4177, 2003.07, alpha,omega-Fluoroalkyl-terminated polystyrenes (alpha,omega-PS(R-f)(2)) with various molecular weights were synthesized by an anionic polymerization. Then, chain end distribution in the surface region of the alpha,omega-PS(R-f)(2) films was studied by angular-dependent X-ray photoelectron spectroscopy in conjunction with neutron reflectivity. The alpha,omega-PS(R-f)(2) films annealed under vacuum exhibited surface localization of chain ends. Since the fluoroalkyl chain ends possess a lower surface free energy compared with the main chain part, they energetically prefer to partition to the surface. The extent to which the chain ends were segregated at the surface was examined as a function of molecular weight. Also, it was presented how surface orientation of the fluoroalkyl end groups was dependent on molecular weight. On the other hand, no segregation of the chain ends was observed at the surface of the alpha,omega-PS(R-f)(2) film annealed in boiled water. This is because the chain ends with a lower surface free energy tend to stay away from the higher energy medium of the boiled water. This result reveals that the surface concentration of chain ends can be regulated by selecting an appropriate annealing condition based on surface thermodynamics. (C) 2003 Elsevier Science Ltd. All rights reserved..
121. ポリメタクリル酸メチル固体膜表面の緩和挙動.
122. A Takahara, K Tanaka, K Akabori, D Kawaguchi, S Tasaki, T Kajiyama, Evaluation of surface composition of polymer blends based on lateral force microscopy., ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, Vol.225, p.U707, 2003.03.
123. T Kajiyama, KI Tanaka, A Takahara, Surface thermal molecular motion of chain end-modified polystyrenes, MACROMOLECULAR SYMPOSIA, 10.1002/masy.200390036, Vol.192, pp.265-270, 2003.03, Surface glass transition temperature, T-g(s), of three classes of monodisperse polystyrene, proton-terminated (PS-H), alpha,omega-diamino-tertninated (alpha,omega-PS(NH2)(2)) and ap-dicarboxy-terminated (alpha,omega-PS(COOH)(2)), were studied by scanning force microscopy. T-g(s) of all samples was discernibly lower than the corresponding bulk glass transition temperature, T-g(b). Also, T-g(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 alpha(a)-relaxation 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 alpha(a)-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 alpha(a)-relaxation process was activated by not only the chain end effect but also the reduced cooperativity at the surface..
124. D Kawaguchi, K Tanaka, T Kajiyama, A Takahara, S Tasaki, Mobility gradient in surface region of monodisperse polystyrene films, MACROMOLECULES, 10.1021/ma025667f, Vol.36, No.4, pp.1235-1240, 2003.02, Surface mobility in polystyrene (PS) films was studied using (PS/deuterated PS) bilayer films, which were prepared by attaching original two surfaces together. Time evolution of the bilayer interface at various temperatures was examined by dynamic secondary ion mass spectroscopy in conjunction with neutron reflectivity. When the bilayer was annealed at a temperature above bulk glass transition temperature, T-g(b), the interfacial thickening was well expressed by the context of Fickian diffusion. On the other hand, in the case of an annealing temperature above surface glass transition temperature, T-g(s), and below T-g(b), the interface monotonically thickened with the time at first and then turned to be independent. This means that chains went across the "mobile" interface and then reached the "dead" bulk region in which the diffusivity should be frozen. Hence, it was claimed that chains could diffuse discernibly in the surface region even at a temperature lower than the T-g(b). On the basis of temperature and molecular weight dependences of quasi-equilibrium interfacial thickness after a sufficiently long time, a possible model of mobility gradient in the surface region was proposed..
125. A Takahara, D Kawaguchi, K Tanaka, M Tozu, T Hoshi, T Kajiyama, Analysis of surface composition of isotopic polymer blend based on time-of-flight secondary ion mass spectroscopy, APPLIED SURFACE SCIENCE, 10.1016/S0169-4332(02)00748-1, Vol.203, pp.538-540, 2003.01, Surface chemical composition of blend composed of monodisperse polystyrene (hPS) with the number-average molecular weight, M-n, of 19.7k and deuterated monodisperse polystyrene (dPS) with M-n of 847k was analyzed based on time-of-flight secondary ion mass spectroscopy (ToF-SIMS). Although hPS possess higher surface free energy than dPS, ToF-SIMS revealed that hPS was preferentially segregated at the outermost surface of the blend films with various compositions. The surface segregation of hPS can be explained in terms of the molecular weight disparity for both components, i.e., an entropic effect. (C) 2002 Elsevier Science B.V. All rights reserved..
126. A Sakai, K Tanaka, T Kajiyama, A Takahara, Thermal molecular motion at surface of atactic polypropylene films, POLYMER, 10.1016/S0032-3861(02)00340-3, Vol.43, No.19, pp.5109-5115, 2002.09, Surface molecular motion in atactic polypropylene (aPP) films was studied by scanning force microscopy. Glass transition temperature at the surface, T-g(delta), was determined to be 251 +/- 1 K on the basis of temperature dependence of lateral force, whereas its bulk glass transition temperature, T-g(b), by dynamic viscoelastic and differential scanning calorimetric measurements was 262 K. In general, polyolefin is easily oxidized, and thus, many kinds of additives are mixed in it for practical use. Hence, effects of oxidation and additives on surface properties of the aPP surface were examined as well. To achieve oxidation, the aPP films were annealed at 428 K for 100 min under the ambient atmosphere. After this treatment, T-g(delta) decreased by approximately 15 K in comparison with the intact film due to degradation of surface chains. On the contrary, in the case of the aPP containing 10 wt% antioxidant, T-g(delta) was almost the same as that of the intact film before and even after the oxidation treatment. (C) 2002 Elsevier Science Ltd. All rights reserved..
127. 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, Vol.35, No.12, pp.4702-4706, 2002.06, The bulk glass transition temperature, T-g(b), of miscible binary blends can be well expressed by the Gordon-Taylor equation. Extending this notion to surface, the surface composition in the blend would be obtained by measuring the surface glass transition temperature, T-g(g), of each constituent as well as their blend. The most intriguing advantage of this technique is that labeling of a component is not necessary, unlike conventional spectroscopy. To confirm the validity of our technique, the surface composition in a mixture of polystyrene (PS) and deuterated PS (dPS) was evaluated and compared with the results by well-established surface characterization techniques, static secondary ion mass spectroscopy, and neutron reflectivity. They were in good accordance with one another within the experimental accuracy. Hence, it was claimed that the proposed method was powerful to study the surface concentration in miscible binary blends. Finally, 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 to an entropic effect..
128. HQ Xiang, K Tanaka, A Takahara, T Kajiyama, Spectroscopic and electrochemical characterizations of dilithium octacyanophthalocyanine Langmuir-Blodgett films, LANGMUIR, 10.1021/la011401a, Vol.18, No.6, pp.2223-2228, 2002.03, Langmuir-Blodgett (LB) films of dilithium octacyanophthalocyanine [Li2Pc(CN)(8)] were first prepared, and their electrochemical reduction/reoxidation behaviors were studied in detail. An overwhelming majority of the Li2Pc(CN)(8) molecules in the LB film were stacked in a face-to-face aggregated state and stood obliquely with an edge-on configuration on the substrate surface. Two overlapping redox waves were observed in the voltammogram of the LB film in I mol dm(-3) HCl solution. Their relative intensity was found to be largely dependent on the molecular aggregation state in the film. On the basis of spectroscopic and electrochemical analyses, the first and second reduction waves upon cathodic potential scanning were principally assigned to the aggregated and monomeric Li2Pc(CN)(8) molecules, respectively, in the solid film structure. In comparison with the corresponding solvent-cast film, charge transfer within the LB film and/or through the electrode interface was facilitated, and the LE film showed excellent dynamic character in the redox process..
129. 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, Vol.34, No.25, pp.8761-8767, 2001.12, Surface glass transition behaviors of monodisperse alpha,omega -diamino-terminated and alpha,omega -dicarboxy-terminated polystyrenes (alpha,omega -PS(NH2)(2) and alpha,omega -PS(COOH)(2)) were studied by scanning force microscopy and were compared with the results of proton-terminated polystyrene (PS-H). All surface glass transition temperatures, T-g(s), of PS-H, alpha,omega -PS(NH2)(2), and alpha,omega -PS(COOH)(2) were discernibly lower than each corresponding bulk glass transition temperature, T-g(b). However, the magnitude of T-g(s) was strongly dependent on the chemical structure of chain end groups, because the surface concentration of chain ends varied with the surface free energy difference between the main chain part and the chain end portion, via the surface segregation or surface depletion of chain ends. This result makes it clear that chain end chemistry is one of determining factors on the magnitude of T-g(s). On the basis of the time-temperature superposition principle applied to the scanning rate dependence of lateral force as a function of temperature, the apparent activation energy, DeltaH(double dagger), of the alpha (a)-relaxation process corresponding to micro-Brownian motion at the surface was evaluated to be approximately 230 kJ mol(-1). This value is much smaller than the reported bulk ones and is independent of the chemical structure of chain ends. This result implies that the cooperativity for the alpha (a)-relaxation process at the PS surface is reduced in comparison with the bulk, probably due to the existence of the free space presented to polymer segments at the surface. Hence, it was concluded that the surface alpha (a)-relaxation process was activated by not only the chain end effect but also the reduced cooperativity at the surface. Finally, possible other factors determining on the magnitude of T-g(s) were discussed..
130. 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, Vol.34, No.18, pp.6420-6423, 2001.08, Scanning viscoelasticity microscopy (SVM) enables one to gain direct access to local viscoelastic properties on solid surfaces. In this study, it was demonstrated how deep the stimulus displacement by a cantilever tip propagated through a film. The glassy polymer/rubbery polymer bilayer prepared on silicon wafer was examined as a model system. Monodisperse polystyrene (PS) and polyisoprene (PI) were used as a glassy polymer for the outermost layer and a fully rubbery one for the underneath phase, respectively. The surface dynamic storage modulus, E ', decreased with decreasing thickness of the upper PS layer due to the contribution from the soft underneath PI layer once the upper layer thickness fell short of 70 nm. On the contrary, surface E ' was invariant for the bilayer with a thicker upper layer. These results indicate that the stimulus displacement imposed propagates to the depth of, at least, 70 nm along the surface normal at room temperature. The SVM measurement was also applied to monodisperse PS thin films with the number-average molecular weight of 140K spin-coated on silicon wafer with native oxide layer. In this case, while surface E ' increased with a decrease in the thickness ranging from 80 nm down to 50 rim on account of the contribution from the hard substrate, it started to decrease for a thinner PS film. This result might imply that the PS surface and/or whole film started to soften up with decreasing thickness, in the case of a PS film thinner than 40 nm..
131. K Kojio, K Tanaka, A Takahara, T Kajiyama, Novel method to prepare organosilane monolayers on solid substrate, BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, 10.1246/bcsj.74.1397, Vol.74, No.8, pp.1397-1401, 2001.08, A novel and convenient method to prepare organosilane monolayers was proposed. Pure water was put onto a cleaned silicon wafer and then a toluene solution of n-trichloro(octadecyl)silane (OTS) was spread on it. X-ray photoelectron spectroscopy and atomic force microscopic observation revealed that an OTS monolayer was successfully formed on the solid substrate after the water was evaporated. The static water contact angle of the silicon wafer covered with the OTS monolayer was 105 degrees. Molecular aggregation states of the OTS monolayer were examined by electron diffraction, Fourier transform infrared spectroscopic. X-ray reflectivity, and grazing incidence X-ray diffraction measurements. The prepared OTS monolayer was in a two-dimensional hexagonal crystalline state at 293 K and alkyl chains of the OTS molecules were oriented normal to the surface. Also, the alkyl chains in the monolayer were highly ordered, although the experimental procedure for the monolayer preparation was quite simple. The development of this novel method to prepare a low energy surface will contribute to the material science as well as having industrial applications..
132. D Kawaguchi, K Tanaka, A Takahara, T Kajiyama, Surface mobile layer of polystyrene film below bulk glass transition temperature, MACROMOLECULES, 10.1021/ma010012k, Vol.34, No.18, pp.6164-6166, 2001.08.
133. HQ Xiang, K Tanaka, A Takahara, T Kajiyama, Reversible reduction and reoxidation of Langmuir-Blodgett films of octacyanophthalocyanine dilithium complex, CHEMISTRY LETTERS, 10.1246/cl.2001.536, No.6, pp.536-537, 2001.06, Langmuir-Blodgett film of octacyanophthalocyanine dilithium complex with strong electron-withdrawing substituents was first prepared and its redox behavior was studied by cyclic voltammetry. The LB film exhibited excellent redox reversibility in an acid electrolyte. In contrast to the case of a solution-casting film, two couples of redox peaks were clearly discerned on the voltammetric curve. Also, the linear dependence of cathodic current on scan rate was kept up to 4000 mV s(-1), which was 10 times larger than that of the solution-casting film..
134. XQ Jiang, CZ Yang, K Tanaka, A Takahara, T Kajiyama, Effect of chain end group on surface glass transition temperature of thin polymer film, PHYSICS LETTERS A, 10.1016/S0375-9601(01)00150-5, Vol.281, No.5-6, pp.363-367, 2001.04, Surface glass transition behaviors of proton end capped poly(2-vinylpyridine) (P2VP-H) and perfluoroalkyl end capped poly(2-vinylpyridine) (P2VP-C2C(8)(F)) thin films were investigated based on temperature-dependent lateral force microscopic (TDLFM) measurement. It is found that the species of chain end groups have significant influence on the surface glass transition temperature of the thin polymer film. For both samples, it is revealed that the surface glass transition temperatures decrease significantly in comparison to the bulk ones, and the magnitude order of reduction in surface Tg for P2VP-C2C(8)(F) is larger than that for P2VP-H. The apparent activation energy of surface cu-relaxation calculated from the Arrhenius plot is ca. 292 +/- 40 and 212 +/- 40 kJ/mol for P2VP-H and P2VP-C2C(8)(F), respectively, and is much smaller than the bulk one. The depression of the surface Tg for thin polymer films is explained by the excess free volume induced by the enrichment of chain end groups at the surface. (C) 2001 Elsevier Science B.V. All rights reserved..
135. Tisato Kajiyama, Daisuke Kawaguchi, Atsushi Sakai, Noriaki Satomi, Keiji Tanaka, Atsushi Takahara, Determination factors on surface glass transition temperatures of polymeric solids, High Performance Polymers, 10.1088/0954-0083/12/4/314, Vol.12, No.4, pp.587-597, 2000.12, The surface molecular motion of monodisperse proton-terminated polystyrene (PS-H), α,ω-diamino-terminated PS (α,ω-PS(NH2)2) and α,ω-dicarboxy-terminated PS (α,ω-PS(COOH)2) films was studied by scanning viscoelasticity microscopy in conjunction with lateral force microscopy. The glass transition temperature Tg, at the surface, Tgs, was found to be markedly lower than bulk Tg, Tgb, and the number-average molecular weight, Mn, dependence of Tgs was more remarkable than that of Tgb. Also, the magnitude of Tgs was strongly dependent on the chain end chemistry. Hence, the activation of surface molecular motion was explained in terms of an excess free volume induced by the preferential surface segregation of chain end groups. The chain end segregation at the film surface was confirmed by dynamic secondary ion mass spectroscopic measurement. However, the Tgs for the PS-H with quasi-infinite Mn was lower than the corresponding Tgb, even though the number density of chain ends was almost negligible. In addition, Tgs for PS films with hydrophilic chain ends, which might be depleted at the film surface, were lower than the bulk values. The apparent activation energy for the surface micro-Brownian motion corresponding to the αa-relaxation process was approximately half of the bulk value. Finally, the depression of Tgs in comparison with Tgb is discussed on the basis of several factors, such as a decreased segment size of molecular motion for the surface αa-relaxation process due to the existence of the free space on the polymer surface and/or a reduced chain entanglement at the surface, in addition to the chain end effect..
136. KAJIYAMA T, SATOMI N, YOKOE Y, KAWAGUCHI D, TANAKA K, TAKAHARA A, Effect of End Group Chemistry on Surface Molecular Motion of Monodisperse Polystyrene Films., Macromol Symp, 10.1002/1521-3900(200010)159:1<35::AID-MASY35>3.0.CO;2-R, Vol.159, pp.35-42, 2000.10.
137. Keiji Tanaka, Atsushi Takahara, Tisato Kajiyama, Rheological analysis of surface relaxation process of monodisperse polystyrene films, Macromolecules, 10.1021/ma000406w, Vol.33, No.20, pp.7588-7593, 2000.10, Surface glass transition temperature, Tg s, of monodisperse polystyrene (PS) films was determined from the temperature dependence of lateral force at a given scanning rate. The end groups of the PS were composed of sec-butyl group and a repeating unit terminated by proton. Tg s of the PS films was discerned to be markedly lower than its bulk Tg, Tg b, in the entire number-average molecular weight, Mn, range, 4.9 K to 1460 K. The Mn dependence of Tg s was analyzed on the basis of a simple power law. The exponent of Mn related to Tg s was -0.60±0.03 in contrast to the power of -0.5 from the Mayes scaling argument that is based on both chain ends being perfectly localized at the surface. This result implies that the surface localization of end groups of the PS used here is not complete. The Tg s extrapolated to the infinite Mn was found to be lower than the corresponding Tg b by approximately 20 K. The apparent activation energy of the surface αa-relaxation process for the PS obtained from Arrhenius plot was 230±10 kJ·mol-1, significantly smaller than that for the bulk PS. Also, it was shown on the basis of Ngai's coupling model that the cooperative motion at the surface can be achieved much easier than its internal bulk phase. Thus, the difference between the Tg s and the Tg b for the infinite Mn PS was explained in terms of the size and/or energy barrier reduction of the cooperative movement for the surface αa-relaxation process, which might be arisen from the existence of the free space presented to polymer segments at the surface..
138. TAKAHARA A, NAKAMURA K, TANAKA K, KAJIYAMA T, Surface Aggregation Structure and Surface Mechanical Properties of Binary Polymer Blend Thin Films., Macromol Symp, 10.1002/1521-3900(200010)159:1<89::AID-MASY89>3.0.CO;2-U, Vol.159, pp.89-96, 2000.10.
139. T. Kajiyama, K. Tanaka, N. Satomi, A. 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, Vol.1, No.1, pp.31-35, 2000.03, 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. © 2000 Elsevier Science Ltd. All rights reserved..
140. Norihiko Miki, Keiji Tanaka, Atsushi Takahara, Tisato Kajiyama, Secondary ion mass spectroscopic analysis of copper migration at the copper/polyimide interface, Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures, 10.1116/1.591191, Vol.18, No.1, pp.313-316, 2000.01, The application of secondary ion mass spectroscopy (SIMS) for the interfacial analysis of copper migration at Cu/polyimide bilayer. The polyamic acid was coated on the Cu substrate and the bilayer was then cured. Copper was found to deeply migrate into the polyimide across its interface. However, the migration phenomena was not detected during vapor deposition of Cu onto the plastic film. Thus, preparation of the bilayer strongly affects Cu migration behavior..
141. T Kajiyama, N Satomi, K Tanaka, A Takahara, Surface, thermal and mechanical characteristics of polymeric solids, MACROMOLECULAR SYMPOSIA, Vol.143, pp.171-183, 1999.08, 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.30 k 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 140 k 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 (DSIMS) 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..
142. T Kajiyama, K Tanaka, A Takahara, Study of the surface glass transition behaviour of amorphous polymer film by scanning-force microscopy and surface spectroscopy, POLYMER, 10.1016/S0032-3861(98)00049-4, Vol.39, No.19, pp.4665-4673, 1998.09, The surface molecular motion of amorphous polymeric solids has been directly measured by lateral force microscopic (LFM), scanning viscoelasticity microscopic (SVM) and differential X-ray photoelectron spectroscopic (D-XPS) measurements. SVM and LFM measurements revealed that the molecular motion on the surface of the monodisperse PS film with Mn less than ca. 30 k was fairly active compared with that in the bulk, mainly due to the surface segregation of chain end groups. The chain end group segregation at the air/PS interface was verified by dynamic secondary ion mass spectroscopic depth profiling of the proton and deuterium ion for end-labelled PS film. These results suggest that surface T-g is depressed because of an increase in free volume near the surface region, induced by the preferential surface localization of chain end groups. D-XPS was utilized for the characterization of surface molecular motion of symmetric poly(styrene-block-methyl methacrylate) diblock copolymer [P(St-b-MMA)] films. It was confirmed by D-XPS that the surface molecular motion of the PS component in [P(St-b-MMA)] diblock copolymer films was gradually activated with decreasing depth from the air/polymer interface. (C) 1998 Elsevier Science Ltd. All rights reserved..
143. K Tanaka, XQ 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, Vol.31, No.15, pp.5148-5149, 1998.07.
144. 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, Vol.31, No.15, pp.5150-5151, 1998.07.
145. Jiang, X, K Tanaka, A Takahara, T Kajiyama, Effect of chain end group hydrophobicity on surface aggregation structure of poly(styrene-block-4-vinylpyridine) symmetric diblock copolymer films, POLYMER, 10.1016/S0032-3861(97)00567-3, Vol.39, No.12, pp.2615-2620, 1998.06, Proton-terminated polystyrene-block-poly(4-vinylpyridine) (P(St-b-4VP)-H) and 3,3,3-trifluoropropyldimethylsilane-terminated polystyrene-block-poly(4-vinylpyridine) (P(St-b-4VP)-C2CF) symmetric diblock copolymers were synthesized by a living anionic polymerization. Differential scanning calorimetry (DSC) measurements revealed that both diblock copolymers were in a microphase-separated state in the bulk. The results of X-ray photoelectron spectroscopy (XPS) measurements revealed that in the case of the P(St-b-4VP)-H film, the surface weight fraction of poly(4-vinylpyridine) (P4VP) decreased drastically on annealing at 432 K for 90 h in order to minimize the magnitude of the free energy at the air-polymer interface, whereas in the case of the P(St-b-4VP)-C2CF film, the surface P4VP weight fraction was almost the same as the bulk value even after annealing at 423 K for 90 h. Also, scanning force microscopy observations (SFM) were in good agreement with the XPS results. These results clearly indicate that the surface molecular aggregation state of the hydrophobic-hydrophilic diblock copolymer film can be controlled by the hydrophobicity of the chain end groups. (C) 1998 Elsevier Science Ltd. All rights reserved..
146. T Kajiyama, K Tanaka, A Takahara, Surface segregation of the higher surface free energy component in symmetric polymer blend films, MACROMOLECULES, 10.1021/ma971247s, Vol.31, No.11, pp.3746-3749, 1998.06.
147. 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, Vol.31, No.3, pp.863-869, 1998.02, Surface molecular aggregation structure and surface molecular motions of high-molecular-weight polystyrene/low-molecular-weight poly(methyl methacrylate) (HMW-PS/LMW-PMMA) blend films were investigated on the basis of X-ray photoelectron spectroscopic measurements and scanning force microscopic observations. Monodisperse PS with M-n = 1450k, where M-n denotes the number-average molecular-weight, and monodisperse PMMAs with M-n 1.2k, 4.2k, 40.5k, 144k, and 387k were used as HMW-PS and LMW-PMMAs, respectively. Static contact angle measurements revealed that the magnitudes of surface free energy, gamma, of PMMAs for all M(n)s studied here were higher than that of PS with M-n = 1450K. In the case of the (HMW-PS/LMW-PMMA) blend films, in which the M-n for each PMMA was less than 144K, PMMA was preferentially segregated at the air-polymer interface, even though PMMA had a main chain with a higher gamma compared with that of PS. It was found from scanning viscoelasticity microscopic measurements that the surface molecular motion of the (PS with M-n = 1450k/PMMA with M-n = 4.2k) blend film was fairly activated in comparison with that of the bulk one due to the surface segregation of LMW-PMMA. The surface enrichment of LMW-PMMA can be explained by enthalpic and entropic terms as follows. (1) Since the magnitudes of gamma of both chair! end groups of a polymer chain synthesized by an ordinary living anionic polymerization are smaller than that of the main chain part, the chain end groups are preferentially segregated at the surface. Therefore, the chain end effect at the air-polymer interface becomes more remarkable with a decrease of M,, due to an increases in the number density of chain end groups. (2) Since polymeric chains existing in a surface region are compressed along the direction perpendicular to the film surface, the surface chains take smaller conformational entropy in a confined state compared with that of bulk chains. The difference in conformational entropy between the surface chain and the bulk one, that is, the conformational entropic penalty of the polymeric chain at the surface, decreases nith a decrease in M-n. Then, when the enthalpic and entropic effects mentioned above overcome the gamma difference of main chain parts between PS and PMMA, PMMA with higher gamma is stably enriched at the blend film surface..
148. K Tanaka, A Takahara, T Kajiyama, Effect of polydispersity on surface molecular motion of polystyrene films, MACROMOLECULES, 10.1021/ma970057e, Vol.30, No.21, pp.6626-6632, 1997.10, Surface molecular motions of monodisperse polystyrene (PS) films, their binary and ternary blend films, and commercially available polydisperse PS films were investigated on the basis of scanning force microscopic (SFM) measurements at 293 K. The monodisperse PSs were synthesized by a living anionic polymerization. The binary and the ternary PS blends were prepared by mixing monodisperse PSs with different molecular weights. The commercially available PSs were used as the polydisperse PS sample. In the case of the monodisperse PS film with number-average molecular weight, M-n, lower than ca. 30k, it was revealed that the surface was in a glass-rubber transition state even at room temperature due to excess free volume induced by the surface localization of chain end groups. SFM measurements revealed that the surfaces of the binary and the ternary PS blend films were in a glass-rubber transition state even at room temperature, when a component with M-n lower than ca. 30k existed. A more vigorous surface molecular motion for the binary and the ternary PS blend films compared with the bulk can be explained by the surface segregation of the lower molecular weight component. In the case of the polydisperse PS film, even though the molecular weight distribution was broad and the somewhat lower molecular weight component was mixed, the active surface molecular motion showing a glass-rubber transition state was remarkably depressed at room temperature in comparison with the case for the monodisperse PS film with corresponding M(n)s. The difference in surface thermal molecular motion between the monodisperse and the commercial polydisperse PS films might be explained on the basis of the chemical structure of the chain end groups. Also, for the case that the lower molecular weight component was not present in the system in spite of the broad molecular weight distribution, the surface molecular motion corresponding to a glass-rubber transition state was not observed at room temperature..
149. 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 spectroscopy, PROCEEDINGS OF THE JAPAN ACADEMY SERIES B-PHYSICAL AND BIOLOGICAL SCIENCES, 10.2183/pjab.73.132, Vol.73, No.7, pp.132-137, 1997.09, 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 uas 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..
150. MOUNIR E A, TANAKA K, TAKAHARA A, KAJIYAMA T, Influence of Interaction between End-Group and Substrate on Dewetting Behavior of Polystyrene Ultrathin Films., 高分子学会予稿集, Vol.46, No.14, pp.4053-4054, 1997.09.
151. WK Lee, JS Yoon, K Tanaka, N Satomi, XQ Jiang, A Takahara, CS Ha, T Kajiyama, Relationships between lateral force and viscoelastic properties for amorphous polymer films based on lateral force microscopy, POLYMER BULLETIN, 10.1007/s002890050161, Vol.39, No.3, pp.369-376, 1997.09, 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 less than or equal to RT decreased with an increase in the scanning rate. Also, poly(vinyl acetate) (PVAc) with Tg greater than or equal to 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..
152. WK Lee, K Tanaka, A Takahara, T Kajiyama, CS Ha, Surface structure of blend films of styrene/acrylonitrile copolymer and poly(methyl methacrylate)(PMMA) or hydrolyzed PMMA, BULLETIN OF THE KOREAN CHEMICAL SOCIETY, Vol.18, No.9, pp.958-961, 1997.09, 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..
153. MONIR E A, TANAKA K, TAKAHARA A, KAJIYAMA T, Effect of End Group-Substrate Interaction on Aggregation State of Polystyrene Ultrathin Films., 化学関連支部合同九州大会講演予稿集, Vol.34th, p.155, 1997.07.
154. T Kajiyama, K Tanaka, A Takahara, Surface molecular motion of amorphous polymeric solids, BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, 10.1246/bcsj.70.1491, Vol.70, No.7, pp.1491-1503, 1997.07, Surface molecular motions of monodisperse polystyrene (PS) films, binary and ternary PS blend films, and polydisperse PS films were investigated on the basis of scanning force microscopic (SFM) measurements at 293 K. The monodisperse PSs were synthesized by a living anionic polymerization. It was revealed that the magnitude of the surface dynamic storage modulus E' was remarkably lower than that for its bulk state, whereas, the surface dynamic loss tangent tan delta value was fairly higher than that for its bulk state, in the case of the monodisperse PS with number-average molecular weight (Mn) lower than 26.6 k. The scanning viscoelasticity microscopic (SVM) measurements showed that the surface of the monodisperse PS film with M-n lower than 26.6 k was in a glass-rubber transition state even at 293 K, even though the bulk T-g was far above 293 K. Lateral force microscopic (LFM) measurements for the monodisperse PS films also revealed that the magnitude of lateral force was dependent on the scanning rate of the cantilever tip in the case of M-n lower than 40.4 k. It is well accepted that the scanning rate dependence of lateral force appears in the case that the surface of the PS film is in a glass-rubber transition state. LFM results correspond well to SVM ones if the scanning rate of the cantilever tip for LFM measurement was converted to the measuring frequency for SVM measurement. Active thermal molecular motion on the polymeric solid 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 (DSIMS) measurement.
The binary and the ternary PS blends were prepared by mixing the monodisperse PSs with different molecular weights. The commercially available PSs were also used as the polydisperse PS samples. LFM and SVM measurements revealed that the surface of the binary and the ternary PS blend films was in a glass-rubber transition state even at room temperature, when the component with M, lower than ca. 30 k existed. More active surface molecular motion compared with the bulk one for the binary and the ternary PS blend films can be explained by the surface segregation of the lower molecular weight component. The surface enrichment of lower molecular weight chains was confirmed on the basis of the DSIMS measurement by using the deuterated PS as the one component. In the case of the polydisperse PS film, even though the molecular weight distribution was broad and a somewhat lower molecular weight component was mixed, the active surface molecular motion showing a glass-rubber transition state was remarkably depressed at room temperature in comparison with the case for monodisperse PS film with the corresponding M(n)s. The difference on the surface thermal molecular motion between monodisperse and polydisperse PS films might be explained on the basis of the chemical structure of the chain end groups. Also, in the case that the molecular weight component lower than ca. 30 k was not present in the system in spite of the broad molecular weight distribution, the surface molecular motion corresponding to the glass-rubber transition was not observed at room temperature.
Also, two-dimensional mapping of topography and surface E' for the [PS/poly(methyl vinyl ether)] ultrathin blend film was carried out by using atomic force microscopy (AFM) and SVM, respectively. The combination of topographical and surface mechanical images could characterize the interfacial structure on nanometer scale..
155. T Kajiyama, K Tanaka, A Takahara, Surface thermomechanical and glass transition temperature measurements of polymeric solids, MACROMOLECULAR SYMPOSIA, Vol.118, pp.677-682, 1997.06, 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..
156. MONIR E A, TANAKA K, TAKAHARA A, KAJIYAMA T, Effect of End Group Functionality on Aggregation Structure of Polystyrene Ultrathin Films., 高分子学会予稿集, Vol.46, No.5, p.905, 1997.05.
157. T Kajiyama, K Tanaka, A Takahara, Surface mechanical properties of polymeric solids, ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, Vol.213, pp.475-POLY, 1997.04.
158. T Kajiyama, K Tanaka, A Takahara, Surface molecular motion of the monodisperse polystyrene films, MACROMOLECULES, 10.1021/ma960582y, Vol.30, No.2, pp.280-285, 1997.01, Forced modulation scanning force microscopic (SFM) and lateral force microscopic (LFM) measurements of the monodisperse polystyrene (PS) films were carried out at 293 K in order to reveal surface molecular motion. Surface dynamic storage modulus, E', and surface loss tangent, tan delta, of the monodisperse PS films were evaluated on the basis of forced modulation SFM measurement. It was revealed that the magnitudes of surface E' and surface tan delta were lower and higher than those for its bulk state, respectively, in the case of the number-average molecular weight (M(n)) lower than 26.6k. Based on forced modulation SFM measurements, the surface of the PS film with M(n) lower than 26.6k was in a glass-rubber transition state even at 293 K, in spite of that the bulk T-g was far above 293 K. LFM measurements for the PS films revealed that the magnitude of lateral force was dependent on the scanning rate of the cantilever tip in the case of M(n) lower than 40.4k. The scanning rate dependence of lateral force appeared in the case that the surface of the PS film was in a glass-rubber transition state. LFM results agreed well with forced modulation SFM ones if the scanning rate of the cantilever tip for LFM measurement was converted to the measuring frequency for forced modulation SPM measurement. The active thermal molecular motion on 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..
159. T Kajiyama, K Tanaka, Ge, SR, A Takahara, Interfacial characteristics of polymer blend ultrathin films based on scanning force microscopy, ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, Vol.212, pp.183-PMSE, 1996.08.
160. A Takahara, K Tanaka, Ge, SR, T Kajiyama, Scanning force microscopic study of morphology and properties of multiphase polymer surface, ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, Vol.212, pp.319-POLY, 1996.08.
161. TAKAHARA A, TANAKA K, GE S‐R, KAJIYAMA T, Scanning force microscopic study of morphology and properties of multiphase polymer surface., Polym Prepr, Vol.37, No.2, pp.589-590, 1996.08.
162. Keiji Tanaka, Atsushi Takahara, Tisato Kajiyama, Film thickness dependence of the surface structure of immiscible polystyrene/poly(methyl methacrylate) blends, Macromolecules, 10.1021/ma951140+, Vol.29, No.9, pp.3232-3239, 1996.04, The film thickness dependence of surface structure for immiscible polystyrene/poly(methyl methacrylate) (PS/PMMA) films was investigated on the basis of atomic force microscopic observation and X-ray photoelectron spectroscopic measurement. In the case of the PS/PMMA film of 25 μm thickness, the air - polymer interfacial region was covered with a PS rich overlayer due to its lower surface free energy compared with that of PMMA and a well-defined macroscopic phase-separated structure was formed in the bulk phase. Also, in the case of the PS/PMMA thin film of 100 nm thickness, the phase-separated structure, in which the PMMA rich domains separated out of the PS rich matrix, formed at the film surface. The formation of the surface structure for the PS/PMMA thin film can be attributed to either the chain conformation or chain aggregation structure being frozen at the air - polymer interfacial region before the formation of a PS rich overlayer due to the fairly fast evaporation of solvent molecules. On the other hand, the two-dimensional PS/PMMA ultrathin film of 10.2 nm thickness did not show distinct phase-separated structure. When the film thickness became thinner than 10.2 nm, the two-dimensional PS/PMMA ultrathin film of 6.7 nm thickness showed fine and distinct phase-separated structure with the domain size of a few hundred nanometers. This structure can be designated as "mesoscopic phase-separated structure". The surface phase state for the two-dimensional PS/PMMA ultrathin films can be explained by the film thickness dependence of both the interaction parameter and the degree of entanglement among polymer chains..
163. Keiji Tanaka, Aki Taura, Shou Ren Ge, Atsushi Takahara, Tisato Kajiyama, Molecular weight dependence of surface dynamic viscoelastic properties for the monodisperse polystyrene film, Macromolecules, 10.1021/ma951378y, Vol.29, No.8, pp.3040-3042, 1996.04, The molecullar weight dependence of the surface viscoelasticity function for the monodisperse PS (polystyrene) films has been investigated on the basis of SVM (scanning viscoelasticity microscope) measurement. In the case of Mn <
26.6K, the film surface is found to be in a glass-rubber transition state or a rubbery state, even at 293K. A depression of the surface Tg compared with that of bulk samples is explained in the basis of the surface localization of chain end groups. SIMS measurements revealed that chain end groups are enriched in the depth range from the outermost surface to Rg..
164. K Tanaka, A Takahara, T Kajiyama, Surface molecular motion in thin films of poly(styrene-block-methyl methacrylate) diblock copolymer, ACTA POLYMERICA, 10.1002/actp.1995.010460612, Vol.46, No.6, pp.476-482, 1995.12, Thin films of poly(styrene-block-methyl methacrylate) diblock copolymer [P(St-b-MMA)] with thickness ca. 50 nm were prepared by a dip-coating method. The surface T-g for the P(St-b-MMA) thin film was evaluated on the basis of the temperature-dependent X-ray photoelectron spectroscopic (TDXPS) measurement. The temperature at which the surface composition started to change was defined as the glass transition temperature, T-g, at the surface region. It was revealed that the surface T-g for P(St-b-MMA) was much lower than that for its bulk sample. Also, the depth dependence of T-g for P(St-b-MMA) was investigated on the basis of the combination of TDXPS and the angular-dependent XPS (ADXPS) method. T-g for P(St-b-MMA) decreased with a decrease in distance from the outermost surface. The molecular weight dependence of the surface T-g for P(St-b-MMA) was more pronounced than that in the bulk sample. and that was expressed as a function of M(n)(-(0.45 +/- 0.02))..
165. 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, Vol.28, No.9, pp.3482-3484, 1995.04.
166. T KAJIYAMA, OHKI, I, K TANAKA, GE, SR, A TAKAHARA, DIRECT OBSERVATION OF SURFACE-MORPHOLOGY AND SURFACE VISCOELASTIC PROPERTIES OF POLYMERIC SOLIDS BASED ON SCANNING FORCE MICROSCOPY, PROCEEDINGS OF THE JAPAN ACADEMY SERIES B-PHYSICAL AND BIOLOGICAL SCIENCES, 10.2183/pjab.71.75, Vol.71, No.2, pp.75-80, 1995.02, Scanning force microscopy (SFM) was applied for the studies of the surface morphology and viscoelastic properties of polymeric solids. Surface morphology of polyethylene (PE) single crystals was studied by atomic force microscopy (AFM) and friction force microscopy (FFM). The AFM observation revealed the lozenge-shaped single crystals of PE with ridgy structure. The FFM experiment revealed that the frictional force on the same sector was dependent on the scanning direction against {110} for the PE single crystal prepared from fractionated HDPE with Mw = 10 k. On the other hand, the frictional force did not strongly depend on the scanning direction for the PE single crystal prepared from unfractionated PE with Mw of 520 k. The FFM results revealed the regularity of chain folding on PE single crystal surface. Nano-mechanical properties of phase-separated polymer surface were imaged by scanning viscoelasticity microscopy (SVM), which has been developed by the authors. Images of dynamic viscoelasticity for both the immobilized (octadecyltrichlorosilane/fluoroalkylsilane) mixed monolayer and [polystyrene(PS)/poly(vinyl methyl ether) (PVME)] blend ultrathin film were presented. SVM could reveal the difference in dynamic viscoelasticity on the phase-separated polymer surface with a nanometer scale resolution..
167. K TANAKA, JS YOON, A TAKAHARA, T KAJIYAMA, ULTRATHINNING-INDUCED SURFACE PHASE-SEPARATION OF POLYSTYRENE POLY(VINYL METHYL-ETHER) BLEND FILM, MACROMOLECULES, 10.1021/ma00108a021, Vol.28, No.4, pp.934-938, 1995.02, Polystyrene/poly(vinyl methyl ether) (PS/PVME) blend films were prepared on hydrophilic SiO substrates by a dip-coating method from toluene solution. The phase-separation temperature of the (PS/PVME) blend films decreased with decreasing film thickness. The (PS/PVME) two-dimensional ultrathin film with a thickness comparable to the dimension of twice the radius of gyration of an unperturbed PVME chain did not show any distinct cloud point. Secondary ion mass spectroscopic (SIMS) measurement for the perdeuterated polystyrene/PVME (dPS/PVME) thin film revealed the selective adsorption of the dPS segments on the hydrophilic substrate in order to minimize the polymer-substrate interfacial free energy. X-ray photoelectron spectroscopic (XPS) measurement showed the enrichment of PVME at the air-polymer interface due to its lower magnitude of surface free energy compared with that of PS. However, the PVME weight fraction at the air-facing surface started to decrease with decreasing film thickness for thickness less than ca. 30 nm. Atomic force microscopic (AFM) observation revealed that the (PS/PVME) two-dimensional ultrathin film with a thickness of 25 nm was in an apparent phase-separated state forming droplet-like domains 200-500 nm in diameter and 20-40 nn in height. Scanning viscoelasticity microscopic (SVM) observation revealed that the droplet-like domains were composed of a PVME-rich phase. These results clearly indicated that the spinodal point decreased below room temperature with decreasing film thickness for thickness less than ca. 30 nm. The formation of the phase-separated domains can be explained by factors such as the negative spreading coefficient of PVME on the PS matrix and the large negative conformational entropy of a PVME chain against stretching..
168. T KAJIYAMA, K TANAKA, OHKI, I, GE, SR, JS YOON, A TAKAHARA, IMAGING OF DYNAMIC VISCOELASTIC PROPERTIES OF A PHASE-SEPARATED POLYMER SURFACE BY FORCED OSCILLATION ATOMIC-FORCE MICROSCOPY, MACROMOLECULES, 10.1021/ma00104a061, Vol.27, No.26, pp.7932-7934, 1994.12.