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Nobuhiro Kawatsuki - One of the best experts on this subject based on the ideXlab platform.
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effects of plasticizer on the transient diffraction properties of polarization holographic gratings made from polarization sensitive polymeric films
Japanese Journal of Applied Physics, 2014Co-Authors: Tomoyuki Sasaki, Nobuhiro Kawatsuki, Kohei Noda, Takashi Shoho, Kotaro Kawai, Hiroshi OnoAbstract:We recorded anisotropic gratings by polarization holographic recording in azobenzene-containing polymeric films doped with a 9-ethylcarbazole (ECZ) plasticizer. Using a polarimeter, we measured in real time the Stokes parameters of the beams diffracted from the gratings. We analyzed these data on the basis of a theoretical model that accounted for the distribution of birefringence caused by Molecular Reorientation as well as for surface relief deformation caused by mass transportation. Our results indicated that increasing ECZ doping level increased the formation speed of the anisotropic grating, but did not greatly affect the amplitude of the photoinduced birefringence.
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photoinduced Reorientation of a liquid crystalline polymer with phenyl benzoate mesogenic side groups on the basis of an axis selective photo fries rearrangement
Macromolecules, 2012Co-Authors: Nobuhiro Kawatsuki, Mami Kurita, Hitomi Matsushita, Teppei Washio, Mizuho KondoAbstract:Many types of photoreactive polymers have been investigated to regulate their Molecularly orientated structures for polarization-controlled optical and display applications. Herein, we demonstrate the axis-selective photoreaction of thin films and their Molecular Reorientation behaviors using four types liquid crystalline poly(meth)acrylates with phenyl benzoate side groups and linearly polarized (LP) 248 nm light. These simple liquid crystalline polymers (LCPs) exhibit sufficient photoinduced Molecular Reorientations. Photoinduced Molecular Reorientation based on an axis-selective photo-Fries rearrangement is simultaneously generated with an in-plane order parameter (S) up to 0.33 when the irradiation temperature is in the lower part of the LC temperature range of the material, but multidomain formation of the mesogenic groups inhibits Reorientation. To prevent thermally generated multidomain formation, an axis-selective photoreaction of an amorphous film followed by thermally generated self-organization...
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Photoinduced Reorientation of a Liquid Crystalline Polymer with Phenyl Benzoate Mesogenic Side Groups on the Basis of an Axis-Selective Photo-Fries Rearrangement
2012Co-Authors: Nobuhiro Kawatsuki, Mami Kurita, Hitomi Matsushita, Teppei Washio, Mizuho KondoAbstract:Many types of photoreactive polymers have been investigated to regulate their Molecularly orientated structures for polarization-controlled optical and display applications. Herein, we demonstrate the axis-selective photoreaction of thin films and their Molecular Reorientation behaviors using four types liquid crystalline poly(meth)acrylates with phenyl benzoate side groups and linearly polarized (LP) 248 nm light. These simple liquid crystalline polymers (LCPs) exhibit sufficient photoinduced Molecular Reorientations. Photoinduced Molecular Reorientation based on an axis-selective photo-Fries rearrangement is simultaneously generated with an in-plane order parameter (S) up to 0.33 when the irradiation temperature is in the lower part of the LC temperature range of the material, but multidomain formation of the mesogenic groups inhibits Reorientation. To prevent thermally generated multidomain formation, an axis-selective photoreaction of an amorphous film followed by thermally generated self-organization processes effectively induce Molecular Reorientation with S up to 0.71 and birefringence (Δn) ∼ 0.16
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photoalignment and photoinduced Molecular Reorientation of photosensitive materials
ChemInform, 2011Co-Authors: Nobuhiro KawatsukiAbstract:Photosensitive materials for photoalignment of liquid crystals (LCs) and photoinduced Molecular Reorientation are described, especially focusing on azobenzene-containing materials and photocrosslin...
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axis selective photo fries rearrangement and photoinduced Molecular Reorientation in liquid crystalline polymer films
Macromolecules, 2011Co-Authors: Nobuhiro Kawatsuki, Takuya Neko, Mami Kurita, Akinobu Nishiyama, Mizuho KondoAbstract:The thermally enhanced photoinduced Molecular Reorientation based on an axis-selective photo-Fries rearrangement was explored for the first time using three liquid crystalline polymethacrylates with 4-(2′-(4″-methoxyphenyl)ethynyl)phenyl benzoate side groups (1a), 4-methoxybiphenyl benzoate side groups (1b), and 4-methoxyphenyl benzoate side groups (1c). All the polymeric films exhibited an axis-selective formation of the photo-Fries products at the phenyl benzoate derivatives side groups by irradiating with linearly polarized (LP) UV light. Annealing the films in the liquid crystalline temperature range of the material greatly amplified the photoinduced small optical anisotropy of the irradiated films. For 1a and 1b, the photoinduced small anisotropy was amplified in a direction parallel to the polarization (E) of LPUV light and the Reorientational order (S) was greater than 0.7. In contrast, the orientation direction was perpendicular to E for 1c (S ∼ 0.57). Finally, a simple double-exposure method usin...
Mizuho Kondo - One of the best experts on this subject based on the ideXlab platform.
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photoinduced Reorientation of a liquid crystalline polymer with phenyl benzoate mesogenic side groups on the basis of an axis selective photo fries rearrangement
Macromolecules, 2012Co-Authors: Nobuhiro Kawatsuki, Mami Kurita, Hitomi Matsushita, Teppei Washio, Mizuho KondoAbstract:Many types of photoreactive polymers have been investigated to regulate their Molecularly orientated structures for polarization-controlled optical and display applications. Herein, we demonstrate the axis-selective photoreaction of thin films and their Molecular Reorientation behaviors using four types liquid crystalline poly(meth)acrylates with phenyl benzoate side groups and linearly polarized (LP) 248 nm light. These simple liquid crystalline polymers (LCPs) exhibit sufficient photoinduced Molecular Reorientations. Photoinduced Molecular Reorientation based on an axis-selective photo-Fries rearrangement is simultaneously generated with an in-plane order parameter (S) up to 0.33 when the irradiation temperature is in the lower part of the LC temperature range of the material, but multidomain formation of the mesogenic groups inhibits Reorientation. To prevent thermally generated multidomain formation, an axis-selective photoreaction of an amorphous film followed by thermally generated self-organization...
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Photoinduced Reorientation of a Liquid Crystalline Polymer with Phenyl Benzoate Mesogenic Side Groups on the Basis of an Axis-Selective Photo-Fries Rearrangement
2012Co-Authors: Nobuhiro Kawatsuki, Mami Kurita, Hitomi Matsushita, Teppei Washio, Mizuho KondoAbstract:Many types of photoreactive polymers have been investigated to regulate their Molecularly orientated structures for polarization-controlled optical and display applications. Herein, we demonstrate the axis-selective photoreaction of thin films and their Molecular Reorientation behaviors using four types liquid crystalline poly(meth)acrylates with phenyl benzoate side groups and linearly polarized (LP) 248 nm light. These simple liquid crystalline polymers (LCPs) exhibit sufficient photoinduced Molecular Reorientations. Photoinduced Molecular Reorientation based on an axis-selective photo-Fries rearrangement is simultaneously generated with an in-plane order parameter (S) up to 0.33 when the irradiation temperature is in the lower part of the LC temperature range of the material, but multidomain formation of the mesogenic groups inhibits Reorientation. To prevent thermally generated multidomain formation, an axis-selective photoreaction of an amorphous film followed by thermally generated self-organization processes effectively induce Molecular Reorientation with S up to 0.71 and birefringence (Δn) ∼ 0.16
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axis selective photo fries rearrangement and photoinduced Molecular Reorientation in liquid crystalline polymer films
Macromolecules, 2011Co-Authors: Nobuhiro Kawatsuki, Takuya Neko, Mami Kurita, Akinobu Nishiyama, Mizuho KondoAbstract:The thermally enhanced photoinduced Molecular Reorientation based on an axis-selective photo-Fries rearrangement was explored for the first time using three liquid crystalline polymethacrylates with 4-(2′-(4″-methoxyphenyl)ethynyl)phenyl benzoate side groups (1a), 4-methoxybiphenyl benzoate side groups (1b), and 4-methoxyphenyl benzoate side groups (1c). All the polymeric films exhibited an axis-selective formation of the photo-Fries products at the phenyl benzoate derivatives side groups by irradiating with linearly polarized (LP) UV light. Annealing the films in the liquid crystalline temperature range of the material greatly amplified the photoinduced small optical anisotropy of the irradiated films. For 1a and 1b, the photoinduced small anisotropy was amplified in a direction parallel to the polarization (E) of LPUV light and the Reorientational order (S) was greater than 0.7. In contrast, the orientation direction was perpendicular to E for 1c (S ∼ 0.57). Finally, a simple double-exposure method usin...
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Photoinduced Molecular Reorientation in photoreactive liquid crystalline copolymers in a phase retarder application
Polymer, 2011Co-Authors: Nobuhiro Kawatsuki, Hiroshi Shoji, Kotaro Yamaguchi, Mizuho Kondo, Kouki TsubakiAbstract:Abstract Polymethacrylate copolymers, which have hexamethylene spacer groups terminated with 4-methoxyphenyl-4′-oxycinnamate (MPC) and 4-oxybenzoic acid (BA) in the side chain, were synthesized. Thin films underwent thermally enhanced photoinduced cooperative Molecular Reorientation using linearly polarized ultraviolet (LPUV) light and subsequent annealing. Moreover, low exposure energy (4–80 mJ cm −2 ) and annealing temperature ( S > 0.5). Tuning the copolymer composition adjusted the birefringence (∆ n ) of homogeneously reoriented films between 0.10 and 0.22 at 517 nm. Finally, a phase retarder (∆ nd = 130 nm) using an oriented copolymer on a triacetylcellulose (TAC) film substrate, which exhibited a thermal stability up to 140 °C, was fabricated.
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thermal nanoimprinting on prealigned photoreactive polymer liquid crystal for Molecular Reorientation
Japanese Journal of Applied Physics, 2010Co-Authors: Makoto Okada, Nobuhiro Kawatsuki, Hiroshi Ono, Mizuho Kondo, Mami Kurita, Sayaka Manabe, Yuichi Haruyama, Kazuhiro Kanda, Akira Emoto, Shinji MatsuiAbstract:Molecular orientation in a photo-crosslinkable liquid crystalline polymer (PLCP) film was explored by a thermal nanoinprinting technique using a SiO2/Si mold with a line-and-space (L&S) pattern. A Molecular oriented structure was confirmed by polarization optical microscopy and diffraction efficiency measurements, at which the reoriented direction was parallel to the mold lines. We demonstrated thermal nanoimprinting on prealigned PLCP films by linearly polarized UV (LPUV) and evaluated the optical characteristics of imprinted PLCP films. As a result, the prealigned PLCP films were reoriented by thermal nanoimprinting.
Katsumi Yoshino - One of the best experts on this subject based on the ideXlab platform.
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electric field tuning of a stop band in a reflection spectrum of synthetic opal infiltrated with nematic liquid crystal
Applied Physics Letters, 2001Co-Authors: Yuki Shimoda, Masanori Ozaki, Katsumi YoshinoAbstract:Electric field tuning of an optical stop band in a reflection spectrum is demonstrated in a synthetic opal thin film infiltrated with liquid crystal. The reflection peak of the opal shifts upon the application of the electric field, and this is based on the refractive index change caused by Molecular Reorientation upon application of a field. The dynamic response of the stop band shift was also studied, and fast response of the order of microsecond was observed.
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ellipsometry of Molecular Reorientation in a freely suspended ferroelectric liquid crystal film
Molecular Crystals and Liquid Crystals, 2001Co-Authors: Sadahito Uto, Masanori Ozaki, Yasuaki Matsumoto, Katsumi YoshinoAbstract:Optical measurements of a field induced Molecular Reorientation process in a freely suspended ferroelectric liquid crystal film (FSFLC) have been studied. In order to measure a direction and a magnitude of a birefringence of the film at the Reorientation, a photoelastic modulator has been used. A complicated response that has broad spectrum of the response speed is observed in the thick FSFLC film that has helical structure.
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Molecular Reorientation and deformation of a freely suspended ferroelectric liquid crystal film
Applied Physics Letters, 1999Co-Authors: Sadahito Uto, Masanori Ozaki, Katsumi YoshinoAbstract:A study of the deformation of a freely suspended ferroelectric liquid crystal film induced by an alternating electric field has been carried out. A notable peak of the magnitude of the deformation was observed at the damping frequency of the Molecular Reorientation. A deformation that depends on the polarity of the applied field was observed in the frequency range higher than the damping frequency of the Molecular Reorientation.
Atsushi Shishido - One of the best experts on this subject based on the ideXlab platform.
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enhancing sensitivity of photoinduced Molecular Reorientation of oligothiophene doped liquid crystals irradiated with a collimated laser beam
Liquid Crystals XXV, 2021Co-Authors: Kohsuke Matsumoto, Koji Usui, Atsushi ShishidoAbstract:Liquid crystals (LCs) have been utilized for the innovative optical devices because the Molecular Reorientation triggers a change in their optical properties. Among them, oligothiophene-doped LCs can induce the Molecular Reorientation by irradiation with a laser beam, which is useful for all-optical devices. However, the photoinduced Reorientational behavior was observed only by irradiation with a high-intensity laser beam. In this study, we investigated the effect of incident light properties on photoresponsive behavior of oligothiophene-doped LCs by irradiation with a collimated laser beam from the perspective of improvement of the photoresponsive sensitivity of the Molecular Reorientation. As a result, the irradiation of oligothiophene-doped LCs with a collimated laser beam enhanced the sensitivity of the Molecular Reorientation.
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Molecular Reorientation behavior of oligothiophene doped polymer stabilized liquid crystals irradiated with collimated laser beam
Molecular Crystals and Liquid Crystals, 2020Co-Authors: Kohsuke Matsumoto, Koji Usui, Norihisa Akamatsu, Atsushi ShishidoAbstract:The irradiation of oligothiophene-doped liquid crystals (LCs) with a linearly polarized laser beam induces homeotropic-to-planar director Reorientation. However, such Molecular Reorientation was ex...
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Effect of surface treatment on Molecular Reorientation of polymer-stabilized liquid crystals doped with oligothiophene
Polymer Journal, 2017Co-Authors: Koji Usui, Erika Katayama, Jing Wang, Kyohei Hisano, Norihisa Akamatsu, Atsushi ShishidoAbstract:Irradiation of dye-doped liquid crystals (LCs) with linearly polarized light leads to Molecular Reorientation, which manifests functional properties for various nonlinear optical (NLO) applications. Material designs with lower light intensity thresholds for Molecular Reorientation have been explored, and nematic LCs have been one of the most attractive choices because of the high NLO properties. Here we present a different approach to reduce light intensity for Reorientation by modifying a substrate surface that controls initial Molecular orientation in polymer-stabilized nematic LCs doped with oligothiophene. The surface of the glass substrate was treated with various concentrations of a silane coupler. Water contact angle measurement and analysis of samples using polarized optical microscopy revealed that surface anchoring in the initial state decreased as the silane coupler concentration decreased. The threshold intensity was successfully reduced by 30% simply by optimizing the silane coupler concentration. This finding clearly indicates that weak surface anchoring is key to the reduction of light intensity for Molecular Reorientation. The Molecular orientation of polymer-stabilized nematic liquid crystals (PSLCs) doped with oligothiophene can be easily manipulated using irradiation with linearly polarized light above a threshold intensity. The photoresponsive behavior depended on the initial Molecular orientation, as controlled by the surface treatment of PSLC cells. The threshold light intensity for Molecular Reorientation was successfully reduced by 30% by optimizing the silane coupler concentration because of the decrease in surface anchoring. Thus, weak surface anchoring leads to a reduced threshold light intensity for Molecular Reorientation.
Mami Kurita - One of the best experts on this subject based on the ideXlab platform.
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photoinduced Reorientation of a liquid crystalline polymer with phenyl benzoate mesogenic side groups on the basis of an axis selective photo fries rearrangement
Macromolecules, 2012Co-Authors: Nobuhiro Kawatsuki, Mami Kurita, Hitomi Matsushita, Teppei Washio, Mizuho KondoAbstract:Many types of photoreactive polymers have been investigated to regulate their Molecularly orientated structures for polarization-controlled optical and display applications. Herein, we demonstrate the axis-selective photoreaction of thin films and their Molecular Reorientation behaviors using four types liquid crystalline poly(meth)acrylates with phenyl benzoate side groups and linearly polarized (LP) 248 nm light. These simple liquid crystalline polymers (LCPs) exhibit sufficient photoinduced Molecular Reorientations. Photoinduced Molecular Reorientation based on an axis-selective photo-Fries rearrangement is simultaneously generated with an in-plane order parameter (S) up to 0.33 when the irradiation temperature is in the lower part of the LC temperature range of the material, but multidomain formation of the mesogenic groups inhibits Reorientation. To prevent thermally generated multidomain formation, an axis-selective photoreaction of an amorphous film followed by thermally generated self-organization...
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Photoinduced Reorientation of a Liquid Crystalline Polymer with Phenyl Benzoate Mesogenic Side Groups on the Basis of an Axis-Selective Photo-Fries Rearrangement
2012Co-Authors: Nobuhiro Kawatsuki, Mami Kurita, Hitomi Matsushita, Teppei Washio, Mizuho KondoAbstract:Many types of photoreactive polymers have been investigated to regulate their Molecularly orientated structures for polarization-controlled optical and display applications. Herein, we demonstrate the axis-selective photoreaction of thin films and their Molecular Reorientation behaviors using four types liquid crystalline poly(meth)acrylates with phenyl benzoate side groups and linearly polarized (LP) 248 nm light. These simple liquid crystalline polymers (LCPs) exhibit sufficient photoinduced Molecular Reorientations. Photoinduced Molecular Reorientation based on an axis-selective photo-Fries rearrangement is simultaneously generated with an in-plane order parameter (S) up to 0.33 when the irradiation temperature is in the lower part of the LC temperature range of the material, but multidomain formation of the mesogenic groups inhibits Reorientation. To prevent thermally generated multidomain formation, an axis-selective photoreaction of an amorphous film followed by thermally generated self-organization processes effectively induce Molecular Reorientation with S up to 0.71 and birefringence (Δn) ∼ 0.16
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axis selective photo fries rearrangement and photoinduced Molecular Reorientation in liquid crystalline polymer films
Macromolecules, 2011Co-Authors: Nobuhiro Kawatsuki, Takuya Neko, Mami Kurita, Akinobu Nishiyama, Mizuho KondoAbstract:The thermally enhanced photoinduced Molecular Reorientation based on an axis-selective photo-Fries rearrangement was explored for the first time using three liquid crystalline polymethacrylates with 4-(2′-(4″-methoxyphenyl)ethynyl)phenyl benzoate side groups (1a), 4-methoxybiphenyl benzoate side groups (1b), and 4-methoxyphenyl benzoate side groups (1c). All the polymeric films exhibited an axis-selective formation of the photo-Fries products at the phenyl benzoate derivatives side groups by irradiating with linearly polarized (LP) UV light. Annealing the films in the liquid crystalline temperature range of the material greatly amplified the photoinduced small optical anisotropy of the irradiated films. For 1a and 1b, the photoinduced small anisotropy was amplified in a direction parallel to the polarization (E) of LPUV light and the Reorientational order (S) was greater than 0.7. In contrast, the orientation direction was perpendicular to E for 1c (S ∼ 0.57). Finally, a simple double-exposure method usin...
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thermal nanoimprinting on prealigned photoreactive polymer liquid crystal for Molecular Reorientation
Japanese Journal of Applied Physics, 2010Co-Authors: Makoto Okada, Nobuhiro Kawatsuki, Hiroshi Ono, Mizuho Kondo, Mami Kurita, Sayaka Manabe, Yuichi Haruyama, Kazuhiro Kanda, Akira Emoto, Shinji MatsuiAbstract:Molecular orientation in a photo-crosslinkable liquid crystalline polymer (PLCP) film was explored by a thermal nanoinprinting technique using a SiO2/Si mold with a line-and-space (L&S) pattern. A Molecular oriented structure was confirmed by polarization optical microscopy and diffraction efficiency measurements, at which the reoriented direction was parallel to the mold lines. We demonstrated thermal nanoimprinting on prealigned PLCP films by linearly polarized UV (LPUV) and evaluated the optical characteristics of imprinted PLCP films. As a result, the prealigned PLCP films were reoriented by thermal nanoimprinting.