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Ryota Mikami, Yuji Sasaki, Hiroshi Orihara
Session ID: 3CO8
Published: 2022
Released on J-STAGE: June 01, 2023
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We perform numerical simulations for a spontaneous pattern formation of umblical defects which are obtained by the reorientation of homeotropically aligned nematic liquid crystals with negative dielectric anisotropy. In this presentation we focus on the stability of the pattern formation by adjusting various physical parameters and external fields. By comparing simulated results with experimental ones, we examine the detailed physical mechanism to stabilize the pattern.
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Shinichiro Oka, Daiichi Suzuki, Kazuki Matsunaga, Tomoki Nishiyama, Ma ...
Session ID: 3L01
Published: 2022
Released on J-STAGE: June 01, 2023
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For future mobile communications such as Beyond 5G and 6G, the application of millimeter wave bands is being considered for high-speed and large capacity communications. However, one of issues of the millimeter wave band is the shielding of radio waves by obstacles. Therefore, we are developing Intelligent Reflecting Surface (IRS) that may contribute to area expansion by utilizing liquid crystal technology. We have confirmed that the developed IRS can reflect radio waves in any direction.
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Satoru Ueno
Session ID: 3L02
Published: 2022
Released on J-STAGE: June 01, 2023
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After introducing tempering in the chocolate manufacturing process, I will introduce a process called melt-mediated transition that causes polymorphic form IV crystallization and melting to quickly generate form V seed crystals during tempering. It is empirically known that more stable polymorphs occur earlier in melt-mediated transitions, but the reason why polymorphisms are promoted is in open-to-question. As for this question, there is the hypothesis that liquid structure in the melt should be existed. In this talk, I will introduce this liquid structure and the discussion about this structure.
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Yoshinobu Tsujii
Session ID: 3L03
Published: 2022
Released on J-STAGE: June 01, 2023
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The reduction of friction and wear directly leads to energy saving and long life of machinery, contributing to a safe and secure sustainable society. While lubrication control, which is the key to this, has become a general-purpose and mature technology, energy loss due to friction is still not small, and a large cutting margin remains. In this lecture, in order to cut into this, the author will talk about the research and development of ultra-low friction interfaces using concentrated polymer brushes and the direction of their applications and discuss their relevance to the liquid-crystal field.
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Chikara Kawakami, Mitsuo Hara, Takahiro Seki
Session ID: PA01
Published: 2022
Released on J-STAGE: June 01, 2023
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The interface between a side-chain liquid crystalline azobenzene polymer film and a low-molecular-mass nematic liquid crystal (NLC) was analyzed over time by the transmission small-angle X-ray scattering measurement method performed inside the LC cell, which was developed in our laboratory. It was found that a higher-order hybrid LC phase, which is not formed by each LC alone, is induced in the vicinity of the azobenzene polymer film immediately after injection of the NLC.
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Saki Mori, Tomohiro Yasui, Shinichi Sakurai, Nobutaka Shimizu, Hideaki ...
Session ID: PA02
Published: 2022
Released on J-STAGE: June 01, 2023
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Cholesteric liquid crystal elastomers (CLCE) are rubbers with the optical properties of cholesteric liquid crystals, and the characteristic wavelength of selective reflection can be reversibly changed by elastic deformation. In this study, we investigate the effects of three deformation modes, (uniaxial extension, compression, and planar extension), on the optical response behavior and helical structure of CLCE. The results show that the changes in the characteristic wavelength and selective reflection properties strongly depend on the deformation modes, even when the strain along the helical axis (z) is the same.
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Kazuyuki Hiraoka, Syunta Asada, Naoki Shimura, Tsubasa Iida, Kouto Oos ...
Session ID: PA03
Published: 2022
Released on J-STAGE: June 01, 2023
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Flexoelectric polarization in liquid crystalline elastomers with wedge-shaped mesogens was investigated. Flexoelectric polarization was fixed in the elastomers that were cross-linked under uniaxial deformation with splay distortion. X-ray diffractometry revealed that the orientational order partially remained at about S = 0.2 even in the temperature region of the isotropic phase designated tentatively as the pseudo-isotropic phase. The electric charge caused by polarization due to the flexoelectric effect was estimated to be -809 pC/mm2 in the splay distorted liquid crystalline elastomers, whereas almost no electric charge was detected in the uniaxially and uniformly aligned elastomers.
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Masato Yamamoto, Hikaru Sanada, Koji Kitagawa, Noboru Ohta, Tsuyoshi K ...
Session ID: PA04
Published: 2022
Released on J-STAGE: June 01, 2023
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A hexa-substituted pentadecyloxyazobenzene-triphenylene linked with propylene ether (1-C15-3) was synthesized and its mesomorphic phase transitions were studied. POM, DSC and synchrotron radiation XRD measurements revealed that this compound exhibits three mesophases and SmA phase and Colr mesophases were detected by XRD.
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Rentaro Yuri, Ryota Ito, Michinori Honma, Toshiaki Nose
Session ID: PA05
Published: 2022
Released on J-STAGE: June 01, 2023
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Summary: Although the liquid crystal(LC) phase shifter is attractive for millimeter wave application, operation speed of the LC phase shifter is extremely slow due to the very long recovery time. In the previous work, we investigated operating characteristics of LC phase shifter under bias magnetic field to improve the recovery speed. However, we could not evaluate accurate effect of magnetic field due to the limitation of measurement speed of Vector Network Analyzer. In this study, we construct fast measurement system by using Gunn diode and diode detector to evaluate the accurate response characteristics.
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Takahide Ishino, Shinji Yudate, Ryotaro Ozaki, Kazunori Kadowaki
Session ID: PA06
Published: 2022
Released on J-STAGE: June 01, 2023
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In recent years, liquid crystal elastomers have been attracting attention because of their characteristics to respond to various stimuli such as temperature response, photoresponse, and mechanical response. In particular, in terms of mechanical response, it has been confirmed that the color of the elastomer changes in response to strain when it is stretched, and this is thought to be caused by a change in the thickness and pitch length of the material due to the stress generated inside the material during stretching. In this study, the SPH method, which is a mesh-free method, is used to analyze the behavior of elastomers when their shapes change dynamically.
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Reo Oto, Souta Takayama, Takahiro Ohkubo, Michinari Kohri, Keiki Kishi ...
Session ID: PA07
Published: 2022
Released on J-STAGE: June 01, 2023
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Spontaneous chiral induction in bent-core liquid crystal molecules is well-known in the field of liquid crystals, but the examples of rod-like molecules are extremely limited. In this study, as a new and simple approach to induce chirality from achiral liquid crystal molecules, we have synthesized rod-like liquid crystal molecules with bent alkyl chains. The results of polarized optical microscopy (POM) and X-ray diffraction (XRD) measurement indicated that B3-Ol has three smectic C liquid crystal phases. By circular dichroism (CD) spectroscopy, CD signals were observed, and we found that the signal intensity varies with the core length.
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Eiki Kawanishi, Jun Yamamoto
Session ID: PA08
Published: 2022
Released on J-STAGE: June 01, 2023
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Molecular manipulator is a method of controlling the concentration distribution of guest molecules in a nematic liquid crystal host with azobenzene additive. Localized irradiation with excitation light induces trans to cis photoisomerization of the azo molecules [1], causing migration of guest molecules in response to spatial modulation of the order parameter. However, cis azobenzene molecules are able to diffuse away from the edge of the irradiated region, blurring the boundary and limiting its applications as a local manipulator. Here, we overcome this issue by using a “push-pull” azobenzene which has significantly shorter cis lifetime, realizing a patterning resolution approximately 10 times that of previous work [2].
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Mirai Motoyama, Junki Yokota, Kohsuke Matsumoto, Miho Aizawa, Kyohei H ...
Session ID: PA09
Published: 2022
Released on J-STAGE: June 01, 2023
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Liquid crystals (LCs) possess unique properties of both fluidity and optical anisotropy. Their molecular orientation and optical properties reversibly change by external stimuli, which leads to the development of various optical applications. In dye-doped LCs, molecular reorientation is induced by the irradiation with a laser beam, resulting in the formation of diffraction rings. Recently, we have reported the ellipsoidal diffraction rings rotating with constant speed by the irradiation of polymer stabilized dye-doped LCs (PSLCs) with a circularly polarized beam. However, the effect of the polymer on the rotation behavior remained unexplored. In this study, we investigated the molecular reorientation and rotation behavior of diffraction rings arising from PSLCs with various polymer concentrations by a pump-probe method.
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Yudai Fuwa, Kyohei Hisano, Osamu Tsutsumi
Session ID: PA10
Published: 2022
Released on J-STAGE: June 01, 2023
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Chiral-nematic liquid-crystalline elastomers (N*LCEs) have a helical molecular orientation exhibiting Bragg reflection at a certain wavelength matched with the helical pitch. Moreover, their helical pitch, i.e., wavelength of the selective reflection, is sensitively changed by mechanical stimuli. We have proposed that this phenomenon is useful to visualize stress and strain applied to the materials. In this study, we developed a N*LCE with an auxetic structure, which shows unique mechanical deformation behavior. The change in helical orientation of N*LCEs due to the pseudo-biaxial stretching of the Auxetic structure was discussed. As a result, the helical pitch length of liquid crystal molecules is significantly reduced, and the helical orientation is maintained.
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Makoto Shibata, Yasushi Okumura, Shizuka Anan, Hirotsugu Kikuchi
Session ID: PA11
Published: 2022
Released on J-STAGE: June 01, 2023
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Liquid crystal/polymer composites (PDLCs) are optical devices that can modulate transparency by applying electric field and are composed of phase-separated polymer and liquid crystal domains as a co-continuous phase. Although PDLCs have already been put to practical use as indoor light-dimming glass, their practical use outdoors has not progressed due to their low electric field responsivity at low temperatures below 0°C. In this study, we fabricate PDLCs using novel analogous monomers with different alkyl chain lengths from those developed by our research group, and aim to verify the electric field responsivity at low temperatures as well as to improve the responsivity.
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吉田 尚生
Session ID: PA12
Published: 2022
Released on J-STAGE: June 01, 2023
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The same liquid crystal alignment configuration of a conventional 90 twisted nematic LC display cell can be obtained in a twisted hybrid alignment liquid crystal cell, we call that a Quasi-Twisted Nematic (Q-TN) mode, when polar anchoring of the homeotropic surface is lower than a critical one. We have numerically clarified relations between elastic constants K11,K22,and K33 of the liquid crystal and the critical anchoring strength to form the Q-TN.
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Atsushi Seki, Mao Suzuki, Ken'Ichi Aoki
Session ID: PA13
Published: 2022
Released on J-STAGE: June 01, 2023
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We synthesized two types of fluorenone derivatives bearing urethane units as hydrogen bonding sites. Their self-assembling behaviors and solvatochromic properties were investigated. The fluorenone-based bilateral asymmetric mono-urethane as well as symmetrical bis-urethane form supramolecular gels in dodecylbenzene. Dilute solutions of the symmetrical bis-urethane show solvatochromism in solvents with various polarities.
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Yuya Ishizaki, Kazuya Hirata, Yuki Nagao, Takahiro Seki, Shusaku Nagan ...
Session ID: PA14
Published: 2022
Released on J-STAGE: June 01, 2023
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Acrylic acid (AA)-containing liquid crystalline (LC) random copolymers P(5OAz10Ac-r-AA) with different AA molar ratios were synthesized via free-radical copolymerization. Thermotropic LC characteristics of P(5OAz10Ac-r-AA)s were evaluated by differential scanning calorimetry measurements and polarized optical microscopy observation. The copolymer thin films exhibited the homeotropic orientation with parallel AA nanochannels to substrates by thermal annealing at the isotropic temperature. The in-plane proton conductivity of the copolymer thin films was determined by electrochemical impedance spectroscopy measurements under controlled temperature and relative humidity conditions. As a result, the proton conductivity increased with the increase of AA contents. For highest AA contents, the proton conductivity exhibited almost no dependence on the film thickness, indicated internal proton conduction through AA nanochannels.
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Eriko Fukuda, Mitsuhiro Akimoto
Session ID: PA15
Published: 2022
Released on J-STAGE: June 01, 2023
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Here we examine which factor of nanoparticles (NPs) is the most important for the improvement of acrylate-based PDLCs cured at a high temperature. We implement a variety of NPs with different sizes and surface functions. We found that NPs with a reactive surface and/or smaller particle size reduces the threshold and saturation voltage of the PDLC device, and curing at a high temperature itself greatly improve the electro-optical performance of acrylate-based PDLCs.
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Izumi Akihiro, Yasuhisa Yamamura, Mafumi Hishida, Kazuya Saito
Session ID: PB01
Published: 2022
Released on J-STAGE: June 01, 2023
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Re-examination of two Schiff base mesogens, 2MBAC and 4MBAC, by DSC, polarized light microscopy, and X-ray diffraction revealed that they exhibit four liquid crystal phases, N, SmA, and two types of SmB phases, on cooling. We discuss the aggregation structures of their smectic phases and the phase transitions.
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Urara Shiina, Osamu Tsutsumi
Session ID: PB02
Published: 2022
Released on J-STAGE: June 01, 2023
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Gold(I) complexes, enabling to show aggregation-induced emission (AIE) property, are attracted to advanced materials for achieving solid-state phosphorescence. Such AIE materials emit light in aggregated state, and their luminescent properties can be tuned by the control of aggregated structure. We have synthesized a rod-like liquid-crystalline gold complexes showing high-quantum-yield phosphorescence even at room temperature in the crystalline state. In this study, we focused on discovery of new functions using mesogenic gold(I) complexes by changing the size of the crystals. We investigated the behavior of crystallization through the fabrication of various size crystals and the evaluation of their luminescence behavior.
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Shogo Mitsuhashi, Masanori Ozaki
Session ID: PB03
Published: 2022
Released on J-STAGE: June 01, 2023
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Blue phase (BP) liquid crystal is expected to be used as electro-optic devices because of its fast response to electric field and characteristic optical properties. The molecular and lattice orientations of BP are seemed to be affected by the device surface, but there are many unclear points. In this study, transmission electron microscopy (TEM) observations were carried out using photopolymerisable BP liquid crystals to observe the lattice orientation of BP in real space. As a result, it was observed that the pattern oriented BP adopt a tilted structure, similar to the expected lattice arrangement.
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Hiroto Nakamura, Hikaru Sanada, Mitsuo Hara, Takahiro Seki, Tsuyoshi K ...
Session ID: PB04
Published: 2022
Released on J-STAGE: June 01, 2023
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A triphenylene derivative which has six 4-tetradecyloxyazobenzene units connected via propylene-ester linkages exhibits both calamitic and discotic LC phases. The SmA-Colr phase transition accompanied by molecular shape change can be reversibly performed by controlling both the temperature and the UV light intensity (λ= 365 nm) under an isothermal condition. The mechanism of the SmA-Colr phase transition under UV-irradiation was studied with GI-SAXS technique to reveal that the amount of cis-isomer of azobenzene unit surely affect the phase transition in the way of destabilizing the mesophases.
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Sota Takebe, Nachia Isobe, Yohei Miwa, Shoichi Kutsumizu, Yasuhisa Yam ...
Session ID: PB05
Published: 2022
Released on J-STAGE: June 01, 2023
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Our starting compound was a nonsymmetric core molecule with benzene (B) and phenylbenzene (PB) at each side of the central group and having docosyloxy chains, denoted as BPB-22, and we introduced a methyl group to the side of the molecular core of BPB-22. As an effect of the side group, we found that the Ia3d-Cub phase was shifted to the lower temperature side as compared to the BPB-22 without a methyl group. We also investigated the aggregation structure of the molecular cores in Ia3d-Cub phase and revealed that the position of the methyl group in the core portion influences the packing structure of the molecular cores (double- or single-layered core states).
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Kohdai Saiki, Shinji Yudate, Ryotaro Ozaki, Kazunori Kadowaki, Hiroyuk ...
Session ID: PB06
Published: 2022
Released on J-STAGE: June 01, 2023
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Tilt angle dependence of selective reflection from patterned cholesteric liquid crystals is analyzed by the FDTD method and our proposed geometric optics method. The long- and short-wavelength of the selective reflection can be estimated by considering the optical path difference and its average refractive index. The calculation results using our proposed method are in good agreement with those using the FDTD method.
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Hikaru Takahashi, Michinari Kohri, Keiki Kishikawa
Session ID: PB07
Published: 2022
Released on J-STAGE: June 01, 2023
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Axially polar-ferroelectric columnar liquid crystals (AP-FCLCs) consist of axially polarized columnar aggregates arranged in parallel, in which their polar directions can be switched and maintained by application or removal of electric field. However, the realization of AP-FCLCs is challenging because the fluidity of the LCs prevents the polarization from maintaining for a long term. To solve this problem, we planned to realize a smooth transition system from the AP-FCLC to the crystal phase without changing the polar structure. As a result, we succeeded in realizing an AP-FCLC compound that transitions from the FCLC to crystal phase at room temperature while maintaining the polarization induced in the LC phase, which is expected to enable semi-permanent maintenance of polarization information.
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Kazuki Shimizu, Atsushi Seki, Ken’Ichi Aoki
Session ID: PB08
Published: 2022
Released on J-STAGE: June 01, 2023
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We have focused on chiral π-conjugated liquid crystals to study bulk photovoltaic effects in ferroelectric liquid crystal phases. In this study, we synthesized several chiral π-conjugated compounds to evaluate their physical properties. We will discuss the influence of the sidechains and π-conjugated core upon the liquid-crystalline and electric properties.
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Akinori Ooka, Jun Yamamoto
Session ID: PB09
Published: 2022
Released on J-STAGE: June 01, 2023
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In liquid crystal nematic gels, self-organized stripe domains can appear in response to certain external stimuli. To gain experimental insights into their formation mechanism, we studied the difference between stripes formed by heating and by applying an electric field, measuring two-dimensional maps of local director characteristics and light transmission using microscope. Director and transmission maps of stripes formed under an electric field are strongly correlated; maps of stripes formed by heating are not. This suggests that the kinetic pathways to gelation in the same physical system are distinct depending on selection of stimulus.
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Rumiko Yamaguchi
Session ID: PB10
Published: 2022
Released on J-STAGE: June 01, 2023
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Polarization variation from visible to THz wavelength ranges has been numerically analyzed in homogeneous and twisted liquid crystal reorientations induced by in-plane electric field. The cell thickness in a nonlinear study is very thick about 100 micron meter. Therefore, linearly polarized visible light passes through the cell with roughly rotating along the LC director direction. THz wave, on the other hand, the light propagates through the cell while changing its polarization state. The LC reorientation director distribution induced by the incident light field should also strongly depend on the light wavelength.
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Daisuke Furuta, Mitsuo Hara, Takahiro Seki
Session ID: PB11
Published: 2022
Released on J-STAGE: June 01, 2023
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Cyanobiphenyl methacrylate monomer was photopolymerized using the RAFT agent segregated on the free surface, then obtained a polymer thin film with monodisperse molecular weight distribution. The liquid crystalline nature of the polymers was evaluated by polarized light microscopy observations and X-ray scattering measurements.
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Keisuke Nakagawa, Ken Ishikawa
Session ID: PB12
Published: 2022
Released on J-STAGE: June 01, 2023
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MC-815 (FLC) and MC-881 (AFLC) mixture was expected to be thresholdless rapid response LC material. However, due to demise of applied research, the detailed physical properties and the mechanism of thresholdless behavior are left unveiled yet. In this study, electric-field-induced birefringence (EFIB) measurements were carried out with several mixtures around 35 wt% of MC-815 in order to research the response to electric field of the mixtures. From the 34.00 wt% result, characteristic temperature dependance of electric field response was observed.
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Tateaki Shikada, Yo Inoue, Hiroshi Moritake
Session ID: PB13
Published: 2022
Released on J-STAGE: June 01, 2023
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This study presents electrically induced refractive index gradient in nematic liquid crystal gels (NLCGs) fabricated by using photopolymerization technique and contact method. Two NLC samples doped with mesogenic monomers at different concentrations are infiltrated into a glass-sandwiched cell with planar treatment from both sides of the cell. Each NLC surface come into contact in the center of the cell, resulting in monomer concentration distribution near the contact region. By photopolymerizing the LC cell after molecular diffusion, a NLCG with polymer concentration distribution can be obtained. When the electric field is applied to the gel, a continuous and large refractive index gradient is observed.
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Yudai Shimada, Mitsuki Fujioka, Kentaro Ikenoya, Shoyo Takei, Yuka Tab ...
Session ID: PB14
Published: 2022
Released on J-STAGE: June 01, 2023
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Mixtures of cyanobiphenyl compounds (nCB) and EBBA are known to exhibit highly ordered smetic phases, resulting from the charge transfer interaction. In this study, we examined the relative amount of transferred charges from EBBA to nCB by IR spectroscopy and compared them to the in-plane lattice constant in the induced SmB phase. The spectroscopy showed that the transferred charges considerably increased at the transition point from the nematic to SmB, followed by the moderate increase with the further decrease of temperature until the saturation at a certain point. On the other hand, the in-plane lattice constant of the induced SmB phase monotonically decreased with a decreasing temperature.
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Yusuke Sakamoto, Hiroyuki Matsukizono, Shizuka Anan, Yasushi Okumura, ...
Session ID: PB15
Published: 2022
Released on J-STAGE: June 01, 2023
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Summary: Recently, our group reported that the surfaces of glass substrates chemically modified with a mixture of two types of silane coupling agents, ethyltrimethoxysilane (C2) and octadecyltrimethoxysilane (C18), showed the high responsivity of liquid crystal director to the external magnetic field in both the azimuthal and polar direction. However, the issue is that previous chemical modification methods have not been sufficiently reproducible. In this study, we developed a reliable and reproducible method to produce omni-directional weak anchoring interfaces by optimizing the chemical modification process of the substrate surfaces.
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Kazutaka Sugai, Mizuki Ito, Hiroshi Noda, Yasuhisa Yamamura, Mafumi Hi ...
Session ID: PC01
Published: 2022
Released on J-STAGE: June 01, 2023
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Phase behavior of PHexOAB/8OCB binary mixtures was investigated using differential scanning calorimetry, polarization microscopy, and small-angle and wide-angle X-ray diffractions. The binary mixtures exhibited the nematic, SmA, and SmB phases depending on the composition. We discuss the phase behavior and the layer spacing of the smectic phases in the binary system.
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Saki Yamashita, Tomoki Murakami, Hiroaki Suzuki, Zhenhua Pan, Kenji Ka ...
Session ID: PC02
Published: 2022
Released on J-STAGE: June 01, 2023
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Liquid crystal (LC) molecules with controllable orientation can undergo spontaneous motion powered by motile molecules or bacteria in these samples. Such motion is often governed by topological defects, which are singularities in the orientation of LCs. To study the influence of topological defects on the motion, a simple and reproducible method for generating these defects is required. In the previous study, topological defects were successfully generated using a micro-wells by the control of the boundary conditions of LC molecules. Currently, we introduced a liquid/LC interface, and the boundary condition was controlled by surfactant molecules at the interface. We found the formation of the topological defects was demonstrated by satisfying the boundary conditions at the interface by the surfactant molecules.
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Keito Konishi, Yuji Sasaki, Hiroshi Orihara
Session ID: PC03
Published: 2022
Released on J-STAGE: June 01, 2023
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When a voltage is applied to a nematic liquid crystal containing ions, a grid-like pattern is observed under crossed polarizers. The appearance of the pattern is affected by the thickness of the insulating films coted on the electrodes. In this study we examine the surface relief structure of the insulating films which are modified with ultraviolet ozone treatment. We found that UVO exposure significantly changes the thickness of the film depending on time. We finally evaluate the effect of relief structure on the pattern formation of nematic liquid crystals.
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Tamon Nakao, Kenta Yamaguchi, Osamu Tsutsumi
Session ID: PC04
Published: 2022
Released on J-STAGE: June 01, 2023
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Summary: Trinuclear gold (I) complexes (Figure 1) exhibit intense luminescence in crystals. Depending on the length of alkyl side-chain on the pyrazole ligands, the complexes showed different color of the luminescence and different liquid crystallinity. In this study, we discussed the relationship between their structure and photophysical/thermal properties. The melting points of complexes were lowered by introduction of branched side-chains, e.g., the complex with the longest branch, DTE6-Hex, showed the melting point at -15 °C and discotic nematic liquid-crystalline phase (ND) in extremely wide temperature range. (Figure 3) The gold complexes were found to exhibit strong phosphorescence at room temperature (Figure 4).
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Hirosato Monobe, Tao Ma, Yu-Jie Zhon, Hai-Feng Wang, Ke-Qing Zhao, Pin ...
Session ID: PC05
Published: 2022
Released on J-STAGE: June 01, 2023
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In this study, mesomorphous butterfly-like shape molecules based on cyclopentadithiophen-4-one and benzodithiophene-4,8-dione core moieties were synthesized. These butterfly-like shape molecules spontaneously self-organize into columnar hexagonal mesophase. The charge carrier mobility was measured by time-of-flight transient photocurrent technique in the mesophases. They display hole-transport performances with positive charge mobility in the 10-3 cm-2 V-1 s-1 range, consistent with the high degree of ordering and stability of the columnar superstructures. One mesogen in particular with benzodithiophen-4,8-dione core (BDTD) shows outstanding ambipolar charge carrier transport with both high electron (μe = 6.6×10-3 cm-2 V-1 s-1) and hole (μh = 4.5×10-3 cm-2 V-1 s-1) mobility values.
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Hiroki Furukawa, Mizuho Kondo, Tomoyuki Sasaki, Moritsugu Sakamoto, Hi ...
Session ID: PC06
Published: 2022
Released on J-STAGE: June 01, 2023
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We have systematically studied the photoinduced reorientation of photoresponsive polymers, especially focusing on the use of N-benzylideneaniline (NBA) as a photoresponsive group. NBA moieties can photoalign based on E-Z-E photoisomerization and can be easily changed to form functional-oriented groups via hydrolysis and re-condensation with functional moieties. In this study, we have achieved in situ conversion to polarized light-emitting films by direct replacement of the end groups.
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Daiki Fukuda, Michinari Kohri, Keiki Kishikawa
Session ID: PC07
Published: 2022
Released on J-STAGE: June 01, 2023
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A liquid crystalline dimer consisting of two cholesteryl moieties linked with nitrophenylene was synthesized. The dimer compound exhibited a chiral nematic liquid crystal phase and its reflective light shifted over a wide wavelength range from red to blue in response to slight temperature changes. The wavelength shift of this chiral nematic compound with respect to temperature was opposite to that of the general chiral nematic compound. Additionally, applying a horizontal voltage caused a change in color tones from red to green. Its phase transition behavior, liquid crystallinity, and reflected light behavior were investigated using polarized optical microscopy (POM), differential scanning calorimetry (DSC), one- and two-dimensional X-ray diffraction (1D-XRD and 2D-XRD), and microscopic reflection spectroscopy.
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Katumasa Taketomo, Le Van Khoa, Take Sasaki, Yumiko Naka
Session ID: PC08
Published: 2022
Released on J-STAGE: June 01, 2023
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Viologens are functional materials responded to various external stimulus. In this study, novel viologen compounds in which an alkyl chain was introduced at the position of the aromatic ring in the asymmetric core (XNNPmY) were synthesized by the Menshütkin reaction, Zincke reactions and anion metathesis reactions (Figure 2). Comparison of 12NNP12 with 12NNPm12 and 12NNP8 with 12NNPm8 showed that the liquid-crystalline (LC) phases appeared at lower temperatures by changing the alkyl chain attached to the aromatic ring of the core moiety from p- to m-position.
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Yuki Ido, Sadahiro Komatsu, Yohei Miwa, Shoichi Kutsumizu, Yasuhisa Ya ...
Session ID: PC09
Published: 2022
Released on J-STAGE: June 01, 2023
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We have been studying the photo-induced phase transition from the smectic (Sm) phase with a one-dimensionally ordered layer structure to the cubic (Cub) phase with a three-dimensional network structure. In this work, we examined a binary system of a Cub-phase-forming molecule ACBC-18 (18 is the carbon number of the alkyl chain) having a cyano group as a lateral substituent and an azobenzene derivative. In this presentation, we describe the results of the thermal phase transition behavior and the Sm-Cub phase transition induced by ultraviolet light irradiation for the above two-component system, based on polarized light microscopic observations and X-ray diffraction measurements.
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Tatsunaga Nakajima, Naoki Hida, Mitsuo Hara, Takahiro Seki, Shusaku Na ...
Session ID: PC10
Published: 2022
Released on J-STAGE: June 01, 2023
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In this paper, we prepared side-chain liquid crystalline (SCLC) copolymers and polymer blends with cyanobiphenyl (CB) and azobenzene (Az) mesogens. Isotropic temperatures of the copolymers and polymer blends shifted higher compared to each homopolymer by differential scanning calorimetry and polarized microscope observation. Moreover, X-ray scattering measurement revealed that the copolymer and blends exhibited the smectic (Sm) E phase at room temperature. Each homopolymer does not exhibit the SmE. These results indicate the induced highly ordered smectic phase formed by the binary mixture of the SCLC copolymer and polymer blends. We discuss the hybrid liquid crystalline phase in main chain structures and side-chain spacers.
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Takahiro Setoguchi, Yasushi Okumura, Shizuka Anan, Hirotsugu Kikuchi
Session ID: PC11
Published: 2022
Released on J-STAGE: June 01, 2023
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We reported that a fluorine-based liquid crystal compound (CnDIO) showed extremely large dielectric anisotropy of 10,000 or more in the ferroelectric nematic (NF) phase, and observed stripe texture called broken Schlieren in the planar surface alignment cell. However, the relationship between polar arrangement and the stripe texture is very unclear. In this study, we evaluate the 3D structure of liquid crystal directors in the stripe texture of CnDIO doped with a dichroic dye using a confocal laser scanning microscope to deduce the polar arrangement in NF phase.
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Kenta Matsumoto, Tatsuya Tomarino, Junya Yamaguchi, Kotaro Kanetada, Y ...
Session ID: PC13
Published: 2022
Released on J-STAGE: June 01, 2023
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In our previous work, it was found that some rod-shaped low molecular compounds containing perfluoroalkyl group at a terminal position exhibited smectic A phase in bulk state and gelated several organic solvents and/or ionic liquids. In this work, two types of fluorine-containing phenyl benzoate derivatives which changed the orientation of ester group were synthesized, and it was considered that the correlation between liquid crystallinity and gelation with [BMIM][TFSA] from the thermodynamic properties, microscope observation, and rheological properties. As the results of them, the 5wt% gels formed by {4-[2-(perfluorohexyl)]ethylsulfanyl}phenyl 4-(octyloxy)benzoate exhibited thixotropy and observed micelle-like texture by polarized microscope.
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Mitsuhiro Akimoto, Misa Hayashi, Eriko Fukuda, Haruna Kosaka
Session ID: PC14
Published: 2022
Released on J-STAGE: June 01, 2023
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Light scattering polarizer consisting of uniaxially stretched polymer-dispersed liquid crystal (PDLC) has attracted attention since it is expected to improve the optical efficiency of conventional LCDs. Light scattering polarizers are made of polyvinyl alcohol (PVA) in which elongated LC microdroplets are dispersed. Here we doped cellulose nanofibers (CNFs) to a LC-PVA composite with the aim to reinforce the mechanical rigidity of the composite. CNFs were obtained from a small brock of bacteria cellulose via the TEMPO-catalyzed oxidation method. We found that the CNF-doped LC-PVA composite is capable of large deformation and the resultant scattering polarizer has an highly improved extinction ratio.
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Toshinobu Takashi, Kaita Suzuki
Session ID: PC15
Published: 2022
Released on J-STAGE: June 01, 2023
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The photorefractive effect of photorefractive liquid crystal mixtures was investigated and appliedto a laser ultrasonic measurement. Photorefractive liquid crystal mixtures, composed of smectic-C liquidcrystals, photoconductive chiral compounds, and a sensitizer, are known to exhibit a fast photorefractiveeffect. The principle of the ultrasonic measurement is that a nanosecond laser pulse is shot on an object tocause an ultrasonic vibration, a continuous laser beam is irradiated on the object, and the ultrasonic variationis detected using photorefractive two-beam coupling. The method can be used to investigate the thicknessand the internal structure of an object without contract.
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Daichi Sato, Yutaka Sumino, Takahiro Yamamoto, Igor Musevic, Yoshiko T ...
Session ID: PD01
Published: 2022
Released on J-STAGE: June 01, 2023
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Liquid crystal (LC) fibers are known to be made by adding specific additives to smectic liquid crystal. Such LC fibers are known to show surface sensitive optical mode, so called Whispering Gallery Mode (WGM), which is expected to be applied to optical devices. However, LC fibers reported in previous studies were unstable structure and easily collapsed into a droplet by temperature. Therefore, optical characteristics of LC fibers could not be sufficiently evaluated. In this study, we will fabricate and investigate LC fibers which contain the polymerizable LC (PLC) monomers and the photoinitiator. We confirmed that the LC fibers with PLC monomers were thicker and had a longer duration than those induced by the LC alone.
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Shogo Yamauchi, Tsuyoshi Fukaminato, Sunnamu Kim, Fuminori Sato, Saimi ...
Session ID: PD02
Published: 2022
Released on J-STAGE: June 01, 2023
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When a photoresponsive chiral molecule is added to a nematic liquid crystal, a cholesteric liquid crystal with a helical structure is formed. The force that induces the helical structure is called helical twisting power (HTP). We have reported reversible light switching in transparent and light-scattered states based on the phase transition between the compensated nematic and cholesteric phases. The development of chiral molecules with large HTPs and ΔHTPs is essential to achieve highly efficient switching. In this study, we synthesize several molecules with alkyl chains and liquid crystalline molecules introduced into the naphthalene ring and study the effect of substituents on torsional forces.
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