Kyushu University Academic Staff Educational and Research Activities Database
List of Papers
Hirotsugu Kikuchi Last modified date:2019.06.28

Professor / nano-organization / Department of Integrated Materials / Institute for Materials Chemistry and Engineering


Papers
1. Takumi Sodemura, Shoichi Kubo, Hiroki Higuchi, Hirotsugu Kikuchi, Masaru Nakagawa, Unimodal Nematic Liquid Crystalline Random Copolymers Designed for Accepting Chiral Dopants, Bulletin of the Chemical Society of Japan, 10.1246/bcsj.20160343, 90, 2, 216-222, 2017, The miscibility of chiral molecules to unimodal side-chain nematic liquid crystalline (LC) polymers was studied to generate chiral nematic phases. Chiral dopants, a phenyl benzoate derivative S-811 and an isosorbide dibenzoate derivative ISO-(6OBA)2 were miscible to the nematic LC polymer PMA(4OPB) tethering phenyl benzoate moieties as side-chain mesogens by preparing mixtures in solutions rather than directly melting the powders together. Nematic LC random copolymers containing non-LC side chains were designed to promote the interaction between mesogens and chiral molecules. The introduction of hexyl chains as side chains randomly into nematic LC polymers improved the miscibility of chiral molecules of an isosorbide dibenzoate derivative with hexyl tails. The hexyl chains of the polymer provided spaces for the chiral molecules and caused alkyl–alkyl interactions. We demonstrated that the randomly introduced hexyl chains promoted the interaction of chiral molecules with LC mesogens to generate chiral nematic phases..
2. Van Bao Bui, Yo Inoue, Hiroki Higuchi, Hirotsugu Kikuchi, Hiroshi Moritake, Response improvement of microstrip line microwave and miliwave phase shifter utilizing polymer stabilized nematic liquid crystal with UV polymerization, IEEJ Transactions on Fundamentals and Materials, 10.1541/ieejfms.137.356, 137, 6, 356-362, 2017, Nowadays as the development of cell phone and satellite communications, liquid crystal materials have attracted considerable attention for realizing these electrically controllable microwave and milliwave components. As usual, nematic liquid crystal is mainly used for microstrip line (MSL) phase shifter, but when driving voltage is removed the response time is very long. In this study, we discuss about using polymer stabilized nematic liquid crystals with UV polymerization for improving the response time in MSL phase shifter in which phase shift is about two times larger than that in CPW phase shifter..
3. Hiroya Nishikawa, Kazuya Shiroshita, Hiroki Higuchi, Yasushi Okumura, Yasuhiro Haseba, Shin Ichi Yamamoto, Koki Sago, Hirotsugu Kikuchi, A highly polar LC material, 24th International Display Workshops, IDW 2017 24th International Display Workshops, IDW 2017, 212-214, 2017.01, An anomalously large dielectric permittivity of about ten thousand is found for an LC compound having a 1,3-dioxane unit in the mesogen core part (DIO). Our experimental results suggest that a ferroelectric-like unidirectional parallel polar arrangement of the molecules is generated along the director in an LC phase of DIO..
4. K. Rijeesh, Hiroki Higuchi, Yasushi Okumura, Jun Yamamoto, Hirotsugu Kikuchi, Liquid crystal anchoring transitions and weak anchoring interface formation at surfaces created by uniquely designed acrylate copolymers, polymer, 10.1016/j.polymer.2016.12.012, 116, 447-451, 2017.05, Weak anchoring of liquid crystals (LCs) can, in principle, have the potential to provide lower operating voltage systems with an improved electro-optic response. The creation of such a liquid crystal system is an important goal for next-generation displays, including polymer-stabilized blue phases. Herein, we report a new method of weak anchoring for LCs in contact with uniquely designed amorphous side-chain copolymers that feature both mesogenic and non-mesogenic units. The mesogenic pendant enhances the compatibility with the LC molecules, while the non-mesogenic part reduces the possible azimuthal anchoring energy of the mesogenic side-chain on LCs. The copolymers with mesogenic pendants bearing polar and non-polar end groups favor planar and homeotropic alignments, respectively. Interestingly, LCs in a glass plate cell coated with these side-chain non-liquid crystalline copolymers showed anchoring transitions and weak anchoring interface formation at precise temperatures. The weak anchoring nature of LCs on copolymer surfaces was confirmed by their easy response to an applied magnetic field. These results suggest that the copolymers perform an important function as weak anchoring surfaces for nematic LCs..
5. H. Yoshida, M. Takahashi, T. Ohkawa, Junichi Fukuda, Hirotsugu Kikuchi, M. Ozaki, Three-dimensional crystal orientation of blue phase liquid crystals on surfaces, Liquid Crystals XXII 2018 Liquid Crystals XXII, 10.1117/12.2323159, 2018.01, Liquid crystalline cholesteric blue phases (BPs) are of high interest for tunable electro-optic applications owing to their fast response times and quasi-polarization-independent phase modulation capabilities. Various approaches have recently been proposed to control the crystal orientation of BPs on substrates, but their basic orientation properties on standard, unidirectionally orienting substrates had not been investigated in detail. Here, detailed studies have been made on the Kossel diagrams of BPs on unidirectionally orienting substrates to understand the three-dimensional crystal orientation of BPs. We find that BPs show strong thermal hysteresis and that the structure of the preceding phase determines the orientation of BPs. Specifically, the BP II-I transition is accompanied by a rotation of the crystal such that the crystal direction defined by certain low-value Miller indices transform into different directions, and within the allowed rotations, different azimuthal configurations are obtained in the same cell depending on the thermal process. Our findings demonstrate that, for the alignment control of BPs, the thermal process is as important as the properties of the alignment layer..
6. Rijeesh Kizhakidathazhath, Hiroki Higuchi, Yasushi Okumura, Hirotsugu Kikuchi, Effect of polymer backbone flexibility on blue phase liquid crystal stabilization, Journal of Molecular Liquids, 10.1016/j.molliq.2018.04.085, 262, 175-179, 2018.07, In this study, we synthesized two novel monofunctional acrylate monomers A0DA and A3DA featuring a benzene core and a dodecyl tail, and then investigated their effect on blue phase liquid crystal (BPLC) stabilization. The benzene core is directly linked to the acrylate unit in A0DA, which forms a rigid polymeric backbone. Whereas in A3DA,a propyl spacer is employed to separate the benzene unit from the acrylate group, thereby allowing backbone mobility. By using A0DA as a monofunctional monomer in the BPLC precursor composite, stabilization of BPLC was not seen upon photopolymerization. Interestingly, the use of A3DA showed successful stabilization of BPI lattice structure after polymerization. These results confirm that the origin of stabilization effect of blue phase is the flexibility of A3DA backbone employed; therefore, the polymeric backbone flexibility is suggested to have a major influence on BP stabilization process. Furthermore, we demonstrated a low voltage electro-optical switching of PS-BPLC built on A3DA, while preserving other desirable properties of BPLC. The present study provides useful insight into monomer designs towards BPLC stabilization and enhancement of electro-optical performance..
7. Takeshi Tsuji, Shota Sakaki, Hideki Fujiwara, Hirotsugu Kikuchi, Masaharu Tsuji, Yoshie Ishikawa, Naoto Koshizaki, Stabilizer-Concentration Effects on the Size of Gold Submicrometer-Sized Spherical Particles Prepared Using Laser-Induced Agglomeration and Melting of Colloidal Nanoparticles, Journal of Physical Chemistry C, 10.1021/acs.jpcc.8b05911, 122, 37, 21659-21666, 2018.09, Pulsed laser melting in liquids (LMLs), a convenient method of submicrometer-sized spherical particle (SMP) preparation, induces nanoparticle (NP) melting and fusion using laser irradiation at a moderate fluence for colloidal NPs. Our earlier study, conducted to produce gold SMPs (AuSMPs) from gold NPs (AuNPs) stabilized by sodium carbonate, demonstrated that the AuSMP size increased concomitantly with decreasing stabilizer concentration, although it has been suggested that laser fluence fundamentally determines the SMP size. This study elucidates an explanation of this phenomenon. Results obtained through experimentation showed the same relation when LML was conducted using AuNPs stabilized by sodium citrate. The narrower size distribution (65 ± 4 nm) of AuNPs used in this study than that of AuNPs used in earlier studies enabled us to ascertain that AuNPs smaller than the source AuNPs (approximately 10 nm diameter) are generated during laser irradiation via AuNP evaporation that occurs simultaneously with the AuNP agglomeration. A theoretical calculation predicts that the temperature increased by laser heating of AuNP depends strongly on the AuNP size, suggesting that efficiencies of stabilizer removal and agglomeration of the 10 nm AuNPs are lower than those of the source 60 nm AuNPs. For that reason, 10 nm AuNPs are likely to remain at high stabilizer concentration, leading to the formation of smaller AuSMPs because of insufficient growth. We also confirmed that such a mechanism (AuNP-size-dependent agglomeration efficiency) is applicable to improve the growth efficiency of AuSMPs on LML using AuNPs prepared by laser ablation in liquids with a wide size distribution. When smaller AuNPs were removed from the colloids by centrifugation, the amount of AuNPs remaining after LML decreased and larger AuSMPs were formed..
8. Daisuke Yoshizawa, Hiroki Higuchi, Yasushi Okumura, Hirotsugu Kikuchi, Relationship between molecular structures of uniquely designed
C 2-symmetric axially chiral dopants and their helical twisting properties in cholesteric liquid crystals, Journal of Materials Chemistry C, 10.1039/c8tc05296d, 7, 8, 2225-2231, 2019.01, The induction of chirality in a liquid crystal (LC) can lead to the development of functional LC materials with enhanced properties. A chiral dopant is known to induce a molecular rearrangement and a subsequent helical twisting in the nematic LC host, affording a cholesteric liquid crystal (CLC). However, the chirality transfer mechanism has not been fully elucidated yet. In this study, we newly synthesized 9,9′-biphenanthrene-type chiral dopants ((S)-2s) following our work on binaphthyl-type chiral dopants with the aim of unveiling the chirality transfer mechanism. The molecular structures of the chiral dopants in the crystal were determined by XRD. Significantly unique Cotton effects were observed in (S)-2s, indicating that (S)-2s adopted a different conformation in solution from the binaphthyl-type chiral dopants. Interestingly, one of the (S)-2s dopants shows positive temperature dependence of helical twisting power (HTP) though most chiral dopants show negative temperature dependence. The effects of mixing chiral dopants having opposite temperature dependence of helical twisting power were also investigated. Finally, a CLC showing temperature independency was obtained by mixing two types of chiral dopants with a reverse trend of temperature dependence in HTP..
9. Daisuke Yoshizawa, Yasushi Okumura, Jun Yamamoto, Hirotsugu Kikuchi, Decreasing the operating voltage of a polymer-stabilized blue phase based on intermolecular affinity, Polymer Journal, 10.1038/s41428-019-0183-6, 51, 7, 667-673, 2019.07, Abstract: This study demonstrates a novel material design strategy to decrease the operating voltage of the polymer-stabilized blue phase (PSBP) based on intermolecular affinity between the chiral dopant and the polymer nanonetworks in the PSBP. We focus on the weak anchoring interface, the so-called “slippery interface”, at which a disordered liquid crystal or isotropic liquid layer is formed between the liquid crystal and polymer. To introduce such a slippery interface inside the PSBP, an isosorbide-based polar chiral dopant is synthesized, and this dopant is expected to show high affinity to polymers with polar substituents. The operating voltage of the PSBP with the polar chiral dopant is considerably decreased with an increasing ratio of polar substituents on the polymer, in striking contrast with the trend observed for the PSBP containing the conventional chiral dopant. Furthermore, the PSBP displays a large electro-optical Kerr constant for the PSBP containing the polar chiral dopant and polymer with the polar substituent. The experimental results suggest that the synthesized chiral dopant with a polar component acts as a chirality inducer for the BP and as a slippery interface inducer via polar-polar interaction with the polymer inside the PSBP..
10. Rijeesh Kizhakidathazhath, Hiroki Higuchi, Yasushi Okumura, Hirotsugu Kikuchi, Weak Anchoring Interface Inducing Acrylate Copolymer Designs for High-Performance Polymer-Stabilized Blue Phase Liquid Crystal Displays, ChemistrySelect, 10.1002/slct.201701233, 2, 23, 6728-6731, 2017.01, Polymer-stabilized blue phase liquid crystal (PS-BPLC) is emerging as a strong competitor for next-generation liquid crystal displays and optoelectronic devices. However, the realization of technologies built on PS-BPLC requires lowering of driving voltage without sacrificing other desirable properties of blue phase liquid crystals. Here, we present a new method for voltage reduction in PS-BPLC based on the stabilization of BPLC with weak anchoring interface inducing acrylate monomers. This method provides significant voltage reduction while maintaining the electro-optical performance of BPLCs at the same time. We believe that this approach has a great potential in developing high-performance photonic devices and displays based on liquid crystals..
11. Yusuke Ishigaki, Hidetoshi Kawai, Ryo Katoono, Kenshu Fujiwara, Hiroki Higuchi, Hirotsugu Kikuchi, Takanori Suzuki, Bis(diarylethenyl)-thiophenes,-bithiophenes, and-terthiophenes
A new series of electrochromic systems that exhibit a fluorescence response, Canadian Journal of Chemistry, 10.1139/cjc-2016-0222, 95, 3, 243-252, 2017.01, 2,5-Bis(diarylethenyl)thiophenes (1) and their bithiophene (2) and terthiophene (3) homologues were designed as a new series of violene/cyanine-hybrid-type electrochromic materials. Alkoxyphenyl and dialkylaminophenyl groups are used as the aryl group in the cyanine parts of 1/2/3O and 1/2/3N, respectively, which emit fluorescence in the neutral state but not in the oxidized state. Voltammetric analyses of 18 newly prepared electron donors show that they all undergo two reversible one-electron oxidations. Redox potentials, UV-vis spectral features, and fluorescence quantum yields are important parameters for characterizing the present electrochromic behavior with a fluorescence response, and can be finely tuned by changing aryl groups in the cyanine part, the number of thiophene rings in the violene part, and the alkyl-chain length of the alkoxyphenyl or diaklylaminophenyl groups (R = CH3, C8H17, C16H33), which makes this a versatile platform for the design of novel electrochromic materials..
12. Hiroya Nishikawa, Kazuya Shiroshita, Hiroki Higuchi, Yasushi Okumura, Yasuhiro Haseba, Shin Ichi Yamamoto, Koki Sago, Hirotsugu Kikuchi, A Fluid Liquid-Crystal Material with Highly Polar Order, Advanced Materials, 10.1002/adma.201702354, 29, 43, 2017.11, An anomalously large dielectric permittivity of ≈10<sup>4</sup> is found in the mesophase temperature range (MP phase) wherein high fluidity is observed for a liquid-crystal compound having a 1,3-dioxane unit in the mesogenic core (DIO). In this temperature range, no sharp X-ray diffraction peak is observed at both small and wide Bragg angles, similar to that for a nematic phase; however, an inhomogeneous sandy texture or broken Schlieren one is observed via polarizing optical microscopy, unlike that for a conventional nematic phase. DIO exhibits polarization switching with a large polarization value, i.e., P = 4.4 µC cm<sup>−2</sup>, and a parallelogram-shaped polarization–electric field hysteresis loop in the MP phase. The inhomogeneously aligned DIO in the absence of an electric field adopts a uniform orientation along an applied electric field when field-induced polarization switching occurs. Furthermore, sufficiently larger second-harmonic generation is observed for DIO in the MP phase. Second-harmonic-generation interferometry clearly shows that the sense of polarization is inverted when the +/− sign of the applied electric field in MP is reversed. These results suggest that a unidirectional, ferroelectric-like parallel polar arrangement of the molecules is generated along the director in the MP phase..
13. Hiroya Nishikawa, Daigou Mochizuki, Hiroki Higuchi, Yasushi Okumura, Hirotsugu Kikuchi, Reversible Broad-Spectrum Control of Selective Reflections of Chiral Nematic Phases by Closed-/Open-Type Axially Chiral Azo Dopants, ChemistryOpen, 10.1002/open.201700170, 6, 6, 2017.12, Invited for this month's cover picture is the groups of Professor Hirotsugu Kikuchi and Dr. Yasushi Okumura at the Institute for Materials Chemistry and Engineering at Kyushu University (Japan). External dynamic control of molecular self-organized superstructures with unique features has been researched, as these structures are applicable to chiral molecular devices. The cover picture shows photocontrol of selective reflection color that originated from the self-organized helical structure of chiral nematic liquid crystals (N*LCs) using closed-/open-type dopants. The drastic structure changes of the dopants by light stimuli enable reversible broad-spectrum control of selective reflections of N*LCs with opposite helical sign. Read the full text of the Full Paper at 10.1002/open.201700121..
14. Hiroya Nishikawa, Daigou Mochizuki, Hiroki Higuchi, Yasushi Okumura, Hirotsugu Kikuchi, Reversible Broad-Spectrum Control of Selective Reflections of Chiral Nematic Phases by Closed-/Open-Type Axially Chiral Azo Dopants, ChemistryOpen, 10.1002/open.201700121, 6, 6, 710-720, 2017.12, We demonstrate reversible RGB-color photocontrol of a chiral nematic liquid crystal (N*LC) by using newly synthesized closed- and open-type chiral dopants. The photoswitching elements in the dopants are azobenzene units on axially chiral binaphthyl cores. Owing to cis–trans photoisomerization of the azobenzene units, both closed- and open-type compounds showed higher solubility, larger helical twisting power (HTP), and larger changes in HTP than conventional chiral dopants in host LCs. Thus, even at very low dopant concentrations, we successfully controlled the chirality of the induced helical structure of the N*LCs. Consequently, the N*LCs reflected right- and left-handed circularly polarized light (CPL) under a light stimulus. In the N*LCs with closed-type chiral dopants, the RGB-color reflection was reversibly controlled within several seconds. Interestingly, the open-type chiral dopant reversibly inverted CPL with opposite handedness in the near and short-wave IR regions. These novel materials are expected to realize new applications and perspectives in color information and similar technologies..
15. Yu Narazaki, Hiroya Nishikawa, Hiroki Higuchi, Yasushi Okumura, Hirotsugu Kikuchi, Substituent effects of bridged binaphthyl-type chiral dopants on the helical twisting power in dopant-induced chiral liquid crystals, RSC Advances, 10.1039/c7ra12465a, 8, 2, 971-979, 2018.01, A new series of chiral dopants, (R)-6,6′-halogenated (1b-1e, X = F, Cl, Br and I) and -methylated (1f) binaphthyl compounds, were designed and synthesized to create chiral liquid crystals by doping them into an achiral nematic liquid crystal (NLC). The influence of halogen (X = F, Cl, Br and I) and methyl substituent factors, such as steric, polar, and polarizability properties, on the helical twisting power (HTP) and their temperature dependences on the chiral dopants were investigated in two host NLCs with different characteristics, fluorinated JC-1041XX and N-(4-methoxybenzylidene)-4-butylaniline (MBBA). The chiral dopants possessing less steric and larger polarizability factors increased the HTP values. The structural similarity and electrostatic arene-arene interactions between the chiral dopants and the NLC molecules also exerted important influences on these values. The temperature dependence of the HTP (HTPt.d.) values also correlated well with the steric and polarizability substituents factors in the two host NLCs. Their correlation coefficients (R2) depended on the molecular structural similarity between the chiral dopant and the NLC..
16. Junichi Fukuda, Yasushi Okumura, Hirotsugu Kikuchi, Numerical calculation of Kossel diagrams of cholesteric blue phases, 2018 Emerging Liquid Crystal Technologies XIII Emerging Liquid Crystal Technologies XIII, 10.1117/12.2286290, 10555, 2018.01, Kossel diagrams visualize the directions of strong Bragg reflections from a specimen with periodic ordering. They have played a pivotal role in the determination of the symmetry of cholesteric blue phases, and in the investigation of their structural changes under an electric field. In this work, we present direct numerical calculations of the Kossel diagrams of cholesteric blue phases by solving the Maxwell equations for the transmission and reflection of light incident upon a finite-thickness blue phase cell. Calculated Kossel diagrams are in good agreement with what is expected as a result of Bragg reflections, although some differences are present..
17. Misaki Takahashi, Takuma Ohkawa, Hiroyuki Yoshida, Junichi Fukuda, Hirotsugu Kikuchi, Masanori Ozaki, Orientation of liquid crystalline blue phases on unidirectionally orienting surfaces, Journal Physics D: Applied Physics, 10.1088/1361-6463/aaaa4b, 51, 10, 2018.02, Liquid crystalline cholesteric blue phases (BPs) continue to attract interest due to their fast response times and quasi-polarization-independent phase modulation capabilities. Various approaches have recently been proposed to control the crystal orientation of BPs on substrates; however, their basic orientation properties on standard, unidirectionally orienting alignment layers have not been investigated in detail. Through analysis of the azimuthal orientation of Kossel diagrams, we study the 3D crystal orientation of a BP material - with a phase sequence of cholesteric, BP I, and BP II - on unidirectionally orienting surfaces prepared using two methods: rubbing and photoalignment. BP II grown from the isotropic phase is sensitive to surface conditions, with different crystal planes orienting on the two substrates. On the other hand, strong thermal hysteresis is observed in BPs grown through a different liquid crystal phase, implying that the preceding structure determines the orientation. More specifically, the BP II-I transition is accompanied by a rotation of the crystal such that the crystal direction defined by certain low-value Miller indices transform into different directions, and within the allowed rotations, different azimuthal configurations are obtained in the same cell depending on the thermal process. Our findings demonstrate that, for the alignment control of BPs, the thermal process is as important as the properties of the alignment layer..
18. Van Bao Bui, Yo Inoue, Hiroki Higuchi, Hirotsugu Kikuchi, Hiroshi Moritake, Response Improvement of Microstrip Line Microwave and Milliwave Phase Shifter Utilizing Polymer Stabilized Nematic Liquid Crystal with UV Polymerization, Electronics and Communications in Japan, 10.1002/ecj.12033, 101, 3, 49-57, 2018.03, With nowadays development of cellular phones and satellite communications, liquid crystal materials have attracted considerable attention for realizing these electrically controllable microwave and milliwave components. As usual, nematic liquid crystal is mainly used for microstrip line (MSL) phase shifter, but when driving voltage is removed, the response time is very long. In this study, we discuss application of polymer stabilized nematic liquid crystals with UV polymerization for improving the response time in MSL phase shifter in which phase shift is about two times larger than that in CPW phase shifter..
19. Fahad Mateen, Heemuk Oh, Wansu Jung, Sae Youn Lee, Hirotsugu Kikuchi, Sung Kyu Hong, Polymer dispersed liquid crystal device with integrated luminescent solar concentrator, Liquid Crystals, 10.1080/02678292.2017.1357845, 45, 4, 498-506, 2018.03, Polymer dispersed Liquid crystal (PDLC) windows are regarded as a good choice for curtain-free windows. However, conventional PDLC needs external electricity to operate, which causes extra energy consumption. These devices cannot be combined with traditional solar cells for energy savings. In this study, a new design of luminescent solar concentrator (LSC)-based PDLC device is presented. In particular, we successfully demonstrate that the PDLC can be integrated with LSC as its back scatter and potentially contributes towards the enhancement of power output by minimising backside light losses. Multi-luminophore LSC is employed to increase the absorption of air mass 1.5 solar irradiance. The edge emission measurements show multiple-luminophore-based PDLC-LSC gives the maximum edge emission power which is 1.7 times more than that of single luminophore-based PDLC-LSC device. Photocurrent measurements are also performed as an additional evidence for the improved performance of PDLC-LSC device. Finally, the visual properties of PDLC-LSC devices are evaluated to realise the compatibility of using such devices in the built environment..
20. H. Yoshida, Anucha Konkanok, Y. Ogawa, Yuto Kawata, M. Ozaki, Jun-ichi Fukuda, Hirotsugu Kikuchi , Bragg reflection band width and optical rotatory dispersion of cubic blue phase liquid crystals, PHYSICAL REVIEW E, 2016.11.
21. Atsuomi Shundo, Yasushi Okumura, Hirotsugu Kikuchi , Keiji Tanaka, Hierarchical spatial heterogeneity in liquid crystals composed of graphene oxides, Phys. Chem. Chem. Phys., 10.1039/C6CP03614G, 18, 22399-22406, 2016.08.
22. Jun-ichi Fukuda, Yasushi Okumura, Hirotsugu Kikuchi , Calculation of confocal microscope images of cholesteric blue phases, Proceedings of SPIE, Emerging Liquid Crystal Technologies XI, 10.1117/12.2209210, 9769, 976906-976906, 2016.03.
23. Kazuhiro Ariki, Seiji Fukushima, Y. Igarashi, T. Hachino, Hiroki Higuchi, Hirotsugu Kikuchi , Variable Optical Attenuator Employing a Dye-Doped (Polymer/Liquid Crystal) Composite Film, 2015 IEEE International Broadband and Photonics Conference, 15-18, 2015.12.
24. Naoto Endo, Takahiro Matsumoto, Hirotsugu Kikuchi , M. Kimura, Study of Polymer-Stabilised Blue Phase Liquid Crystal on a Single Substrate, Liq. Cryst., 10.1080/02678292.2015.1055602, 43, 66-76, 2016.01.
25. Hirotsugu Kikuchi , Shogo Izena, Hiroki Higuchi, Yasushi Okumura, Kenji Higashiguchi, A Giant Polymer Lattice in a Polymer-Stabilized Blue Phase Liquid Crystal, Soft Matter, 10.1039/c5sm00711a, 11, 4572-4575, 2015.06.
26. G. Lim, Jae-Hyun Hwang, Hirotsugu Kikuchi , Sung-Kyu Hong, Effect of Reactive Monomer Concentration on Electro-Optical Properties in Polymer-Stabilized Blue Phase Liquid Crystals with Identical Chiral Dopant Concentrations, Mol. Cryst. Liq. Cryst., 10.1080/15421406.2014.956398, 609, 54-60, 2015.05.
27. Yuto Kawata, H. Yoshida, Shu Tanaka, Anucha Konkanok, M. Ozaki, Hirotsugu Kikuchi , Anisotropy of The Electro-Optic Kerr Effect in Polymer-Stabilized Blue Phases, PHYSICAL REVIEW E, 10.1103/PhysRevE.91.022503, 91, 022503, 2015.06.
28. S. Fukushima, Kazuhiro Ariki, Koki Yoshinaga, Hiroki Higuchi, Hirotsugu Kikuchi , Infrared Extinction of a Dye-Doped (Polymer/Liquid Crystal) Composite Film, Crystals, 10.3390/cryst5010163, 163-171, 2015.03.
29. Beomjong Kim, Yeon Jung Um, Seongun Jeon, Hirotsugu Kikuchi , Sung-Kyu Hong, Enlargement of Blue-Phase Stability for Rod-Like Low-Molecular-Weight Chiral Nematic Liquid Crystal Mixtures, Liq. Cryst., 10.1080/02678292.2014.936531, 41, 1619-1626, 2014.05.
30. Takumi Inadomi, Shogo Ikeda, Yasushi Okumura, Hirotsugu Kikuchi , Nobuyoshi Miyamoto, Photo-Induced Anomalous Deformation of Poly(N-Isopropylacrylamide) Gel Hybridized with an Inorganic Nanosheet Liquid Crystal Aligned by Electric Field, Macromol. Rapid Commun., 10.1002/marc.201400333, 35, 1741-1746, 2014.07.
31. Takanori Suzuki, Keisuke Hanada, Ryo Katoono, Yusuke Ishigaki, Hiroki Higuchi, Hirotsugu Kikuchi , Sho Higasa, Kenshu Fujiwara, Hidetoshi Yamada, Takanori Fukushima, Electrochiroptical Response in Aqueous Media: 9,10-Dihydrophenanthrene-9,10-diyl Dications with Michlar’s Hydrol Blue Chromophores Attached with Oligoethylene Glycol Units, CHEMISTRY LETTERS, 10.1246/cl.140163, 43, 982-984, 2014.05.
32. G. Lim, Hirotsugu Kikuchi , Sung-Kyu Hong, Effect of Cyanobiphenyl Homologue Molecules on Electro-Optical Properties in Liquid Crystal Blue Phases and Polymer-Stabilized Blue Phases, Polymer Journal, 10.1038/pj.2013.98, 46, 337-341, 2014.05.
33. Hiroyuki Yoshida, Shuhei Yabu, Hiroki Tone, Yuto Kawata, Hirotsugu Kikuchi , Masanori Ozaki, Secondary Electro-Optic Effect in Liquid Crystalline Cholesteric Blue Phases, OPTICAL MATERIALS EXPRESS, 10.1364/OME.4.000960, 4, 960-968, 2014.04.
34. K. Kakisaka, Hiroki Higuchi, Yasushi Okumura, Hirotsugu Kikuchi , A Fluorinated Binaphthyl Chiral Dopant for Fluorinated Liquid Crystal Blue Phases, J. Mater. Chem. C, 10.1039/c4tc01049c, 2, 6467-6470, 2014.07.
35. Hirotsugu Kikuchi , K. Kakisaka, Hiroki Higuchi, Yasushi Okumura, Novel 6,6 '-Difluoro-substituted Binaphthyl Derivatives as Chiral Dopants for Fluorinated Nematic Liquid Crystals, CHEMISTRY LETTERS, 10.1246/cl.131169, 43, 5, 624-625, 2014.05.
36. G. Lim, Yasushi Okumura, Hiroki Higuchi, Hirotsugu Kikuchi , Low-Temperature Properties of Polymer-Stabilised Liquid-Crystal Blue Phases, CHEMPHYSCHEM, 10.1002/cphc.201301142, 15, 7, 1447-1451, 2014.05.
37. H. Tone, H. Yoshida, S. Yabu, M. Ozaki, Hirotsugu Kikuchi , Effect of anisotropic lattice deformation on the Kerr coefficient of polymer-stabilized blue-phase liquid crystals, PHYSICAL REVIEW E, 10.1103/PhysRevE.89.012506, 89, 1, 2014.01.
38. T. Nguyen, S. Umeno, Hiroki Higuchi, Hirotsugu Kikuchi , H. Moritake, Improvement of decay time in nematic-liquid-crystal-loaded coplanar-waveguide-type microwave phase shifter by polymer stabilizing method, JAPANESE JOURNAL OF APPLIED PHYSICS, 10.7567/JJAP.53.01AE08, 53, 1, 2014.01.
39. K. Kaneko, K. Oto, T. Kawai, H. Choi, Hirotsugu Kikuchi , N. Nakamura, Electrorheological Effect and Electro-Optical Properties of Side-on Liquid Crystalline Polysiloxane in a Nematic Solvent, CHEMPHYSCHEM, 10.1002/cphc.201300093, 14, 12, 2704-2710, 2013.08.
40. M. Kimura, N. Nagumo, T. N. Oo,, N. Endo, Hirotsugu Kikuchi , T. Akahane, Single-substrate polymer-stabilized blue phase liquid crystal display, OPTICAL MATERIALS EXPRESS, 10.1364/OME.3.002086, 3, 12, 2086-2095, 2013.12.
41. H. Yoshida, S. Yabu, H. Tone, Hirotsugu Kikuchi , M. Ozaki, Electro-optics of cubic and tetragonal blue phase liquid crystals investigated by two-beam interference microscopy, Appl. Phys. Express, 6, 062603, 2013.06.
42. H. Yoshida, S. Yabu, H. Tone, Hirotsugu Kikuchi , M. Ozaki, Electro-optics of cubic and tetragonal blue phase liquid crystals investigated by two-beam interference microscopy, Appl. Phys. Express, 6, 062603, 2013.06.
43. S. Niiyama, Hirotsugu Kikuchi , Observation of Transient Phase Separation Progess of Liquid Crystal/Polymer Composites Obtained by Photo-Polymerization Induced-Phase Separation and their Electro-Optical Properties, Engineering Sciences Reports, Kyushu University, 34, 1-7, 2013.01.
44. S-K. Hong, C. Kim, S. Park, Hirotsugu Kikuchi , Blue Phase Stability of n-OCB Homologue Chiral Nematic Liquid Crystal Mixtures, Liq. Cryst., 40, 446-449, 2013.04.
45. S. Shibayama, Hiroki Higuchi, Yasushi Okumura, Hirotsugu Kikuchi , Dendron-Stabilized Liquid Crystalline Blue Phases with an Enlarged Controllable Range of the Photonic Band for Tunable Photonic Devices, Adv. Funct. Mater., 23, 2387-2396, 2013.12.
46. S. Yamamoto, Y. Haseba, Hiroki Higuchi, Yasushi Okumura, Hirotsugu Kikuchi , Lattice plane control of liquid crystal blue phase, Liq. Cryst., 40, 639-645, 2013.04.
47. S. Niiyama, Hirotsugu Kikuchi , Optical Microscopic Observation of Morphology in Liquid Crystal/Polymer Composites and their Electro-Optical Properties, Mol. Cryst. Liq. Cryst., 577, 1-14, 2013.05.
48. F. Zhu, T. Nishimura, T. Sakamoto, H. Tomono, H. Nada, Yasushi Okumura, Hirotsugu Kikuchi , T. Kato, Tuning the stability of CaCO3 crystals with magnesium ions for the formation of aragonite thin films on organic polymer templates, Chem. Asian J., 8, 3002-3009, 2013.08.
49. G. Lim, Yasushi Okumura, Hiroki Higuchi, Hirotsugu Kikuchi , Temperature dependence of dielectric and electro-optical properties and disordered structure in polymer stabilized blue phases at low temperature, Digest of Technical Papers - Society for Information Display International Symposium, 44, 1273-1275, 2013.06.
50. S. Fukushima, T. Hachino, Hiroki Higuchi, Y. Igarashi, K. Yoshinaga, Hirotsugu Kikuchi , Metal-complex-doped polymer/liquid-crystal composite film operating at wide wavelength range, Pacific Rim Conference on Lasers and Electro-Optics, CLEO - Technical Digest,, art. no. 6600200, 2013.07.
51. M. Kimura, N. Nagumo, T. N. Oo, Hirotsugu Kikuchi , T. Akahane, Bendable display device using polymer-stabilized blue phase liquid crystal, Proceedings of the 20th International Workshop on Active-Matrix Flatpanel Displays and Devices: TFT Technologies and FPD Materials, AM-FPD 2013, 6600200, 2013.04.
52. H. Choi, Hiroki Higuchi, Y. Ogawa, Hirotsugu Kikuchi , Polymer-Stabilized Supercooled Blue Phase, Appl. Phys. Lett., 101, 131904/1-131904/5, 2012.09.
53. K. Higashiguchi,, K. Yasui, M. Ozawa, K. Odoi,, Hirotsugu Kikuchi et al., Spatial Distribution Control of Polymer Nanoparticles by Liquid Crystal Disclinations, Polymer Journal, 44, 632-638, 2012.04.
54. S. Yamamoto, T. Iwata, Y. Haseba, D.-U. Cho, S.-W. Choi, Hiroki Higuchi, Hirotsugu Kikuchi , Improvement of Electro-Optical Properties on Polymer-Stabilised Optically Isotropic Liquid Crystals, Liq. Cryst., 39, 487-491, 2012.04.
55. Haseba, Y; Yamamoto, S; Kuninobu, T; Sago, K; Nagano, Y; Kikuchi, H, Optically Isotropic Liquid Crystals for Electrooptical Devices, Digest of Technical Papers - Society for Information Display International Symposium, 42, 206-209, 2011.08.
56. Choi, H; Higuchi, H; Kikuchi, H, Chiral Pitch Dependence of Electro-Optic Kerr Effect in Polymer Stabilized Blue Phase, Digest of Technical Papers - Society for Information Display International Symposium, 42, 1658-1660, 2011.08.
57. Choi, H; Higuchi, H; Kikuchi, H, Determination of Polar Anchoring Strength for Polymer-Stabilized Blue Phase Liquid Crystal Device, Jpn. J. Appl. Phys., 50, 325104/1-325104/5, 2011.08.
58. Choi, H; Higuchi, H; Kikuchi, H, Electrooptic response of liquid crystalline blue phases with different chiral pitches, Soft Matter, 7, 4252-4256, 2011.08.
59. Choi, H; Higuchi, H; Kikuchi, H, Fast electro-optic switching in liquid crystal blue phase II, Appl. Phys. Lett., 98, 131905/1-131905/3, 2011.08.
60. Lyu, JJ; Kikuchi, H; Kim, DH; Lee, JH; Kim, KH; Higuchi, H; Lee, SH, Phase separation of monomer in liquid crystal mixtures and surface morphology in polymer-stabilized vertical alignment liquid crystal displays, J. Phys. D-Appl. Phys., 44, 325104/1-325104/5, 2011.12.
61. Mizunuma, T; Oo, TN; Nagano, Y; Ma, HY; Haseba, Y; Higuchi, H; Okumura, Y; Kikuchi, H, Electro-optical properties of polymer-stabilized blue phase with different monomer combination and concentration, Opt. Mater. Express, 1, 1561-1568, 2011.12.
62. Oo, TN; Mizunuma, T; Nagano, Y; Ma, HY; Ogawa, Y; Haseba, Y; Higuchi, H; Okumura, Y; Kikuchi, H, Effects of monomer/liquid crystal compositions on electro-optical properties of polymer-stabilized blue phase liquid crystal, Opt. Mater. Express, 1, 1502-1510, 2011.12.
63. Yabu, S; Tanaka, Y; Tagashira, K; Yoshida, H; Fujii, A; Kikuchi, H; Ozaki, M, Polarization-independent refractive index tuning using gold nanoparticle-stabilized blue phase liquid crystals, Opt. Lett., 36, 3578-3580, 2011.06.
64. Yabu, S; Yoshida, H; Lim, G; Kaneko, K; Okumura, Y; Uehara, N; Kikuchi, H; Ozaki, M, Dual frequency operation of a blue phase liquid crystal, Opt. Mater. Express, 1, 1577-1584, 2011.06.
65. Lee, M; Hur, ST; Higuchi, H; Song, K; Choi, SW; Kikuchi, H, Liquid crystalline blue phase I observed for a bent-core molecule and its electro-optical performance, JOURNAL OF MATERIALS CHEMISTRY, 20, 5813-5816, 2010.06.
66. Hong, SK; Choi, HS; Shibayama, S; Higuchi, H; Kikuchi, H, Blue Phase Temperature Range at n-Cyanobiphenyl Homologue Chiral Nematic Liquid-Crystal Mixtures, MOLECULAR CRYSTALS AND LIQUID CRYSTALS, 528, 32-37, 2010.06.
67. Shibayama, S; Higuchi, H; Kikuchi, H, Synthesized Novel Dendritic Molecules and Broadening of Temperature Range in Liquid Crystalline Blue Phases, Prodeedings of IDW'10, 41-44, 2010.12.
68. Choi, H; Higuchi, H; Kikuchi, H, Electro-optic Response of Blue Phases, Prodeedings of IDW'10, 1787-1791, 2010.12.
69. K. Kuroiwa, H. Kikuchi, N. Kimizuka, Spin crossover characteristics of nanofibrous Fe-II-1,2,4-triazole complexes in liquid crystals, Chem. Commun., 46, 8, 1229-1231 , 2010.01.
70. S-W. Choi, S. Yamamoto, Y. Haseba, *H. Kikuchi, Correlation between the electro-optical Kerr effect and physical parameters of nematogens, Opt. Mater, 32, 1, 190-193, 2009.05.
71. T. Iwata, K. Suzuki, H. Higuchi, H. Kikuchi, A method for enlarging the Kerr constant of polymer-stabilised blue phases, Liq. Cryst., 36, 9, 947-951, 2009.11.
72. H. Yoshida, Y. Tanaka, K. Kawamoto, H. Kubo, T. Tsuda, A. Fujii, S. Kuwabata, H. Kikuchi, *M. Ozaki, Nanoparticle-Stabilized Cholesteric Blue Phases, Appl. Phys. Exp., 2, 12, 121501, 2009.11.
73. M. Ojima, T. Noma, H. Asagi, A. Fujii, M. Ozaki, H. Kikuchi, Effect of Mixed Cellulose Ester Membrane Structure on Appearance of Cholesteric Blue Phases, Mol. Cryst. Liq. Cryst., 512, 1982-1988 , 2009.05.
74. H-H. Lee, JS. Yu, JH. Kim, S. Yamamoto, H. Kikuchi, Fast electro-optic device controlled by dielectric response of planarly aligned cholesteric liquid crystals, J. Appl. Phys., 106, 1, 014503, 2009.05.
75. M. Ojima, T. Noma, H. Asagi, A. Fujii, M. Ozaki, H. Kikuchi,, Pinning Effect of Mixed Cellulose Ester Membrane on Appearance of Cholesteric Blue Phases, Appl. Phys. Exp., 2, 2, 021502, 2009.11.
76. S-W. Choi, S. Yamamoto, T. Iwata and H. Kikuchi, Optically isotropic liquid crystal composite incorporating in-plane electric field geometry, J. Physic D: Applied Physics, 2009.05.
77. D-U. Cho, T. Iwata, S.-W. Choi, S. Yamamoto, H. Higuchi, H. Kikuchi, Polarization Analysis of Nanostructured Chiral LC Composites, Mol. Cryst. Liq. Cryst., 2009.06.
78. S.-K. Hong, G.-H. Lim and H. Kikuchi, Thickness Dependence of Blue Phase Transition Behavior of Chiral Nematic Liquid Crystal, Mol. Crust. Liq. Cryst., 2009.06.
79. H. Kikuchi, Y. Haseba, S. Yamamoto, T. Iwata, H. Higuchi, Optically Isotropic Nano-structured Liquid Crystal Composites for Display Applications, Digest of Technical Papers - Society for Information Display International Symposium, 2009.06.
80. 5. T. Iwata, K. Suzuki, N. Amaya, H. Higuchi, H. Masunaga, S. Sasaki, and H. Kikuchi, Control of Cross-Linking Polymerization Kinetics and Polymer Aggregated Structure in Polymer-Stabilized Liquid Crystalline Blue Phases, Macromolecules, 42 (6), 2002-2008, 2009.02.
81. K. Higashiguchi, K. Yasui, K. Kikuchi, Direct Observation of Polymer-Stabilized Blue Phase I Structure with Confocal Laser Scanning Microscope, J. Am. Chem. Soc., Vol. 130(20), 6326-6327, 2008.05.
82. T. Noma, M. Ojima, H. Asagi, Y. Kawahira, A. Fujii, M. Ozaki, H. Kikuchi, Effects of polymer network surfaces on expansion of cholesteric blue phases temperature, e-Journal of Surface Science and Nanotechnology, Vol. 6, pp.17-20, 2008.05.
83. K. Higashiguchi, K. Yasui and H. Kikuchi, Direct Observation of Polymer-Stabilized Blue Phase I Structure with Confocal Laser Scanning Microscope, J. Am, Chem. Soc., 130, 6326-6327, 2007.04.
84. S-W. Choi, S. Yamamoto, Y. Haseba, H. Higuchi and H. Kikuchi, Optically isotropic-nanostructured liquid crystal compositewith high Kerr constant, Applied Physics Letters, Vol. 92, 043119, 2008.01.
85. N. Uchiyama, H. Hasuo, M. Yamaguchi, Y. Furuya, H. Kikuchi, Development of (polymer/liquid crystal) composite film for high-speed photo shutter, Kenkyu Hokoku - Fukuoka-ken Kogyo Gijutsu Senta, 17, 20-23, 2007.08.
86. H. Kikuchi, Y. Haseba, T. Iwata, H. Higuchi, Fast Electro-Optical Switching in Polymer-Stabilized Liquid Crystalline Blue Phases for Display Application, 38(Bk. 2), 1737-1740, 2007.05.
87. T. Iwata, T. Takaoka, K. Suzuki, N. Amaya, H. Higuchi, H. Kikuchi, The Influence of Thermal Property of The Polymer on The Polymer-Stabilized Blue Phase, Molecular Crystals and Liquid Crystals, 470, 11-18, 2007.08.
88. Y. Haseba, H. Kikuchi, Optically Isotropic Chiral Liquid Crystals Induced by Polymer Network and Their Electro-Optical Behavior, Molecular Crystals and Liquid Crystals, 470, 1-9, 2007.08.
89. H. Kikuchi, S. Hirata, K. Uchida, Confocal Laser Scanning Microscopic Observation of Polymer-stabilized Blue Phase I, Mol. Cryst. Liq. Cryst, Vol.45, pp. 283-288, 2007.03.
90. K. Izumi, T. Nagamura, H. Kikuchi, Light Diffraction Studies on Director Arrangement in Polymer-pinned Striped Pattern Obtained via the Electric Field-induced Fredericks Transition of Nematics, Liquid Crystals, Vol. 33, 665-670 (2006), 2006.07.
91. Y. Haseba and H. Kikuchi, Electro-optic Effects of the Optically-Isotropic Phase Induced by Incorporative Effects of Polymer Network and Chirality of Liquid Crystal, J. Soc. Info. Display, Vol. 14, 551-556 (2006), 2006.10.
92. S. Yokoyama, S. Mashiko, H. Kikuchi, K. Uchida, and T. Nagamura, Laser Emission from Polymer-Stabilized Liquid Crystalline Blue Phases, Advanced Materials, Vol. 18, pp. 48-51( 2006)., 2006.01.
93. Vol. 9(2), 82-95(2005)..
94. H. Kikuchi, Y. Hisakado, K. Uchida, S. Hirata, Y. Hirata, T. Nagamura, Fast Electro-Optical Switching in Polymer-Stabilized Blue Phases, Proceedings of IDW, LCT1-2, 21-24(2005)..
95. Y. Haseba, H. Kikuchi, T. Nagamura, Large Electro-optic Kerr Effect in Nano-structured Chiral Liquid Crystal Composites over a Wide Temperature Range, Advanced Materials, Vol. 17, pp. 2311-2315,(2005).
96. Y. Hisakado, H. Kikuchi, T. Nagamura and T. Kajiyama, Large electro-optic Kerr effect in polymer-stabilized blue phases, Advanced Materials, 10.1002/adma.200400639, 17, 1, 96-+, Vol. 17, 96-98, 2005.01.