Pattern formation in a liquid crystal light valve with optical feedback is investigated numerically on the basis of a phenomenological model. Under the rotational feedback with 30 degrees, a six-hold petal pattern appears in a certain voltage regime. As the increase of applied voltage, the petal pattern begins to fluctuate and changes to spatiotemporal chaos. The static and dynamical features of the petal patterns obtained in the numerical simulation are very similar to the experimental observations. The numerical simulation reveals the scenario of bifurcation from the static petal pattern to the fluctuating petal pattern under the increase of applied voltage.

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We found novel patterns formed at phase separation in the mixture of a nematic liquid crystal and silicone oil. Besides the regular array of straight chains reported (Nature 407, 611 (2000)), more complex self-assembled patterns of polymer droplets including the branched chains and horizontal chains are observed. In this study, we studied the kinetic process of phase separation combining the transformation of topological defects in details by using polymers of high viscosity.

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We report the synthesis and behaviors of rodlike molecules possessing a biphthalimide core. The biphenyl part generates a twist structure. We expected that a helical super structure was constructed by aggregation of the molecules with one chirality, and the two imide parts have a large dipole to organize the molecules. Some of the compounds exhibited a smectic A (SmA) phase. However the helical structure wasn't confirmed.

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Cholesteric Liquid Crystals are helical periodic structures exhibiting a psuedo one-dimensional photonic band-gap along the helical axis. Upon introduction of a structural defect in the lattice by methods such as laser-induced pitch modulation, photonic defect modes are exhibited in the selective reflection band of the cholesteric liquid crystal. By certain templating methods, functional structural defects with optical or electrical response can be introduced in the periodic structure. In this study, the tuning characteristics of the defect-modes in cholesteric liquid crystals with functional structural defects are investigated.

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Cyanobiphenyl-based compounds with various ligand groups have been synthesized as protecting agents for metal nanoparticles, aiming at improvement of metal nanoparticle-doped LC displays. Protected Pd nanoparticles have been prepared with these protecting agents. The size distribution of nanoparticles was examined by TEM observation. Dispersibility in common organic solvents and liquid crystals was studied by light scattering behavior and microscopic observation. Comparison with biphenyl-based compounds without cyano groups was also examined to prove coordination structures and the effects of cyano groups.

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A ferroelectric liquid crystal can be expected to realize not only high-speed response but also microsizing of pixel when applying it to the display device. In this research, we examined the influence of the microscopically patterned electrodes on the molecular alignment of a ferroelectric liquid crystal.

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In this research, we built anisotropic diffraction gratings in Polymer Dispersed Liquid Crystal (PDLC) by using two coherent laser beams with intensity-modulation light, resulting in periodical uniform Liquid Crystal(LC) director orientation due to the recording time and phase separation. Higher diffraction efficiencies can be obtained by longer recording time that significantly changed the orientation of the LC to become twisted 90 degree from perpendicular alignment to parallel with grating vector. Longer recording time induced continuous phase separation and large density of LC droplet which finally almost completed grating configuration has been observed. By the addition of ultraviolet exposure, polymerization of unreacted monomer occurred and the diffraction efficiency increased again.

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We have investigated the three component liquid micro-emulsion system made by conventional liquid crystal(7ocb), perfluorinated liquid crystal(BI) and purfluorinated oil, and found following novel phase transition behaviors:i) Near I-N phase transition: We have found the clear orientation fluctuation mode by DLS measurement above I-N phase transition before anisotropic nematic phase appear under polarizing microscope observation. Existence of the transparent nematic phase can be strongly expected as similar to the inverse micelle dispersed in the nematic phase. ii) In the vicinity of the N-SmA phase transition: We have found anomalous critical slowing down of the orientation fluctuation just above N-SmA phase transition.

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Discotic liquid crystals composed of Triphenylene cores with polyethylene oxide (PEO) tails showed nematic discotic phase (ND phase) in a wide temperature range. Phase transition from a ND phase to a nematic columnar phase (Ncol phase) was triggered by the addition of alkali metal salts. In this report, we investigated the influence of a counter ion on the stability of ND phase.

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We prepared thin films of liquid crystalline azobenzene (Az) block copolymers consisting of polydimethylsiloxane block by spin-coating method from a chloroform solution. After irradiation of linear polarized UV light under annealing at LC temperature, the smectic layer of the Az block was aligned perpendicular to the polarization plane of the irradiation light. Moreover, the induced anisotropy of Az chromophores was deleted by photo induced phase transition of LC block at temperature less than below the isotropic transition point.

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The bistability of molecules are associated with either the internal freedoms in molecular structure or electronic structure (spin, charge, etc.) of an individual molecule or those of an assembly of molecules (relative orientation and arrangement). In order to couple the process occurring at molecular level with a macroscopic event, we aim at the redox-active metallomesogens. Previously, a direct electrochemical activity of metallomesogens was demonstrated for the first time on the columnar liquid crystalline phases at an ambient temperature. Here we report non-thermal, redox-induced phase transformation of metallomesogens from a columnar liquid crystal to an isotropic ionic liquid.

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The mixture of (1R,2R)-bis{4-(5-decyl-2-pyrimidinyl)phenyloxymethyl}cyclohexane (1) and 5-heptyl-2-{4-(4-pentylphenyl)phenyl}pyrimidine (BP57) showed unusual alignment phenomena at the nematic phase. The alignment of the liquid crystalline molecules were changed with temperature. In order to study the relationship between 1 and host liquid crystals, 1 was added to several liquid crystals. We report the relationship between the structures of the host liquid crystals and unusual alignment phenomena.

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Thermal behavior of 4-pentyl-4'-isothiocyanatobiphenyl (5TCB), which shows crystal E phase (Cr E) as its mesophase, was investigated from 6 to 360 K by adiabatic calorimetry. The Cr E phase and other two crystalline phases were detected below its fusion and the thermodynamic quantities associated with the phase transitions were estimated. The alkyl chain length dependences of the entropy of the ordered crystal - Cr E phase and Cr E - isotropic liquid phase transitions of nTCB (n = 2 - 10) suggest that the intramolecular disorder of the Cr E phase is the same as that of the isotropic liquid phase. The motion of the alkyl chain of nTCB plays an important role for the formation of Cr E phase.

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The crossed anisotropic gratings were recorded in polymer dispersed liquid crystals (PDLC) by overwriting the holographic gratings at the same place. The optical anisotropy, which was linked with director of the liquid crystals, was intensively studied on varying the writing conditions. The optical anisotropy was strongly dependent on the writing conditions such as exposure energy and crossing angles.

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Photo-cross\linkable copolymer liquid crystal containing 4-methoxycinnamoyloxy groups and glycidyl methacrylate (GMA) groups were synthesized, and its application to photoalignment layer for LCs were investigated. Synthesized copolymer exhibit a nematic liquid crystalline phase despite of the copolymer comprise 60% GMA group. A thin film was irradiated with linearly polarized (LP) light after subsequently were annealed at liquid crystalline temperature, where induced the molecular reorientation of the film was observed. In addition the nematic liquid crystal was aligned on this polymer film parallel to the elective vector of the LP light. The film is useful for the LC alignment layer for LCDs devices.

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Here we report on the development of new liquid-crystalline materials based on amino acids. Oligo-α-peptide derivatives, oligo-γ-peptide derivatives having glutamic acid moieties, and oligo-β-peptide derivatives having aspartic acid moieties have been synthesized to examine the effects of the peptide-backbone structures on the liquid-crystalline properties. These oligopeptides formed thermotropic hexagonal columnar phases.

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We have studied the orientation of liquid crystalline polymer (LCP) film. In this research, the functionalized and surface alignment controlled LCP film was fabricated by over-coating fluorine-containing polymer onto the LCP film. The single LCP film has hybrid alignment and large dependence on incident light angle on retardation. In contrast, fluorine-containing polymer over-coated LCP film has lower dependence on incident light angle. It suggests that homogeneous alignment film was obtained by using fluorine-containing polymer / LCP bilayer system. We will also describe in detail concerning the property of overcoat material and the effect of annealing condition of overcoat film.

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Radical polymerization of dialkyl fumarates (DRFs) is one of the good candidates to obtain substituted methylene-type polymers. By introducing mesogenic groups to fumarate, new side-chain liquid crystal polymers with comb-like structure were established. From the standpoint to give enough polymerizability and chirality, a chiral diol obtained by the reduction of L-lactate was used as the junction group between fumarate corpus and functional side chains. The relationship between the development of liquid crystallinity and the existence of chirality proximal to the main-chian was studied.

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Simultaneous measurements of rheological and dielectric properties were made to clarify the shear-induced structural changes in the nematic phase of 8CB (4-n-octyl-4'-cyanobiphenyl). Varying the shear rate, viscosity and the dielectric permittivity were measured precisely as a function of temperature, finding the shear diagram specifying the stable structural regions of the respective shear-induced structures. In the transient response of the dielectric permittivity after the steady shear flow is applied, different behaviors are observed between the flow-alignment region (b*) and the director-precession regions (a-b, am, as, a(b), ac); a monotonous change is observed in the former region while a damped oscillation in the latter regions. Based on these results, shear-induced structures in the nematic phase will be discussed.

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Optically compensated bend (OCB) mode device exhibits fast response and wide viewing angle. In the OCB mode cell, side-chain type polyimide has been used as a alignment layer since high pretilt angle is required. The amount of the side chain changes the surface structure of the polyimide alignment layer, and has an influence on the device properties. In this study, we have been prepared various polyimides and investigated the effects of the polyimide alignment layers on the splay-bend orientation transition in the OCB cell.

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New optically active compounds were synthesized from (1S,2S)-trans-1,2-cyclohexanedicarboxylic acid. All compounds have two mesogenic moieties and bent structure. Some compounds didn't show liquid crystalline phase, while the compounds having flexible spacers between the cyclohexane and the mesogenic moieties showed mesomorphic properties. In this study, we report the liquid crystalline properties about these compounds.

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We have investigated the shape-memory effect of uniaxially deformed main-chain smectic C elastomers. In the uniaxially deformed smectic C elastomer, the reversible deformation such as shrinkage and elongation is observed in a heating and cooling process in which the smectic-isotropic (isotropic-smectic) transition takes place. We confirm that the strength of layer reflection in X-ray observation becomes weak after the uniaxial deformation. The shape-memory effect of the elastomers and the molecular re-orientation under mechanical stress are discussed.

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The rubbing treatment with cloth on polymer film is one of the methods to give an ability for alignment property for liquid crystal molecules. Device parameters such as the anchoring strength, pretilt angle and static electricity are required to be evaluated in advance. In this study, Nematic liquid crystal cells with polyimide alignment film was prerubbed by various kind of rubbing cloths and their device parameters were evaluated.

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We studied mesomorphism of the BF2 complexes having 3,4,5-trialkoxy-substituted aryl rings(alkoxy group: CnH2n+1O n=1, 8, 12, 16) by polarized optical microscopy, differential scanning calorimetry and temperature-dependent X-ray diffraction techniques. As the result, these BF2 complexes of n=8, 12, 16 showed a hexagonal columnar mesophase. Although rod-like molecules like these present complexes cannot form the columnar structure, they form disk-like dimers to enable them show columnar structure.

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We studied the polarization-selective photoreaction and molecular reorientation in photocrosslinkable polymer liquid crystals(PPLCs).The PPLCs with tolane mesogenic moieties which exhibits large birefringence. Influence of tolane moiety groups on the reorientational behavior in polymer liquid crystals is investigated.

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We have investigated the molecular alignment and the phase transition behavior in a mixture of a typical thermotropic smectic liquid crystal [4-(methylheptyloxycarbonyl) phenyl 4'-octyloxybihenyl-4-carboxylate:MHPOBC] and a chain-like molecule [such as octane and hexane]. Myelin texture was observed in polarized microscopy of the mixture in the temperature region where the mesophases were confirmed in the DSC thermogram. A typical smectic X-ray image was also observed in temperature dependent X-ray measurements, which revealed that the layer thickness abruptly increased at the phase transition temperature from crystal to smectic. In addition, quadrupolar splitting was observed in 2H-NMR spectra of the chain-like molecule, because it was ordered in the smectic phase. Accordingly, not only the liquid-crystalline molecule but also the chain-like molecule took part in the architecture of the smectic structure appearing in the mixture.

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We report the synthesis, behaviors, and organization of liquid crystalline dimmers consisting of two mesogens linked with a biphenyl moiety. Their properties were investigated by polarized optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). They exhibited a smectic A (SmA) phase. The layer distance observed in the XRD was shorter than the molecular length calculated in the molecular modeling. The molecular packing structure was postulated.

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We propose a two-dimensional (2D) cell parameter measurement system with a telecentric video lens for determining a cell thickness, twist angle and pretilt angle of a large screen liquid crystal (LC) display. The 2D cell parameter distributions can be determinated by measuring Stokes parameters of the LC cell as changing an oblique angle of the incident light upon the LC cell.

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Here we report on liquid-crystalline properties of new thiophene-based molecules having an ion-responsive phosphine oxide moiety. These molecules exhibit thermotropic hexagonal columnar phases in wide temperature ranges including room temperature. In addition, the incorporation of sodium triflate to these molecules induces the formation of micellar cubic phases by ion-dipole interactions.

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Azo-containing polymers, poly(DR1m-co-M6PBMe), having push-pull type of azo-group and phenyl benzoate ester group were prepared and their photo-orientation behaviors were investigated. They were infiltrated into silica inverse opal, and resulting composites were found to show reversible Bragg reflection shift under irradiation of light in a range of 500 nm to 600 nm. With linearly polarized light, the Bragg reflection band of inverse opal was shifted to longer wavelength region, because the refractive index contrast was changed by the alignment ability of azobenzene compounds perpendicular to the axis of incident polarized light. On the other hand, with unpolarized light, the Bragg reflection band was shifted to shorter wavelength region. This blue shift was due to the molecular orientation preferring parallel to the incident light direction.

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Seven kinds of pyrene derivatives having four ester-type branched side-chains (PCm-n) were prepared. Six of them were crystalline but were found to show discotic columnar phases by forming CT complexes with electron acceptors, TeNF and TrNF, by DSC and POM mesurement. On the other hand, PC6-6 was shown to form ordered rectangular columnar phase (Colro) by XRD measurement.

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When colloidal particles are dispersed in nematic liquid crystal, the alignment of nematic liquid crystal is deformed by anchoring force at the surface of the particles. When we impose strong and homeotropic anchoring, particle itself becomes topological defect, and another defect emerges near the particle at the same time. Interaction between particles with such particles has been explained by analogy of electrostatics. We succeeded in making such pairs of defects and measuring the interparticle force directly by dual optical tweezers system.

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We demonstrate the effect of the ferroelectric nanoparticles dispersed in the alignment layer of a TN LC panel. The TN LC panel with alignment layer doped with ferroelectric nanoparticles shows much higher contrast ratio in comparison to the ordinary TN LC panel with commonly used polymide layer. The effects of BTO nanoparticles in several different concentrations have been studied. Among which 2.5 wt% and 5 wt% BTO mixtures show better performances. Higher concentrations as 10wt%, 15wt%, and 20wt% have also been studied. No improvement has been found in these cases. Surface textures of the alignment layers have also been studied by AFM. Nematic liquid crystal ZLI-4792 has been used for this study.

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A wide range of liquid crystal pretilt angles can be achieved by preparing different concentration ratios of homogenous polyimide and homeotropic polyimide. We realized a high pretilt surfaces even though nanostructures were not observed as reported in [1]. Measurement of pretilt angles was carried out by an ellipsometric crystal-rotation method using anti-parallel homogeneous cells having both rubbed blend-coated substrates. Moreover,pretilt angles of sample cells, whose innersurfaces were treated with prerubbed blend-PI substrate and transcribed PMMA-coated substrate respectively, were also measured.

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Aligned beta-phase poly(9,9-dioctylfluorene) (F8) thin films have been prepared and their optical properties have been examined. The polarization ratio in photoluminescence (PL) of aligned beta-phase F8 thin films is 30 and is almost the same as that in aligned crystalline F8 thin films, while PL quantum efficiency is improved from 44 % (aligned crystalline F8 thin films) to 67 % (aligned beta-phase F8 thin films). These results suggest that aligned beta-phase F8 thin films are applicable to the improvement of performance of polarized organic light-emitting diodes.

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A novel approach for expanding the stable temperature range of liquid crystalline blue phases, which are a coexisted state of ordered regions and disordered ones, by using the liquid crystal mixtures with a broad coexisting temperature range of a nematic and isotrpic phases.

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New chiral dopants for nematic liquid crystals were synthesized from an optically active 4,4,4-trifluoro-3-(6-methoxy-2-naphthyl)butanoic acid, and their helical twisting power (HTP) values were determined. The ketone-linked chiral dopant showed the largest HTP value. The chiral dopant having the linear structure showed relatively large HTP value.

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Photoconductive chiral dopants with two different molecular structures were synthesized. In order to add the photoconductivity to on FLC, photoconduvtive moiety was introduced to the chiral dopants. A terthiophene was chosen as a photoconduvtive moiety. It was confirmed that the liquid crystalline mixtures exhibited ferroelectricity, and the phase transition behavior was investigated. The photorefractivity was measured by two-beam coupling experiment.

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Fundamental investigation of flexible liquid crystal display modes with in-plane electric field have investigated. This display mode has an electrode structure with a cell thickness. Therefore, liquid crystal cell with a merit of small undulation of cell thickess and adhesion will be realized. This display mode is interesting for a function of an ideal cell thickness and an in-plane electric field.

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Poly(methacrylate) copolymer containing 95mol% of photoreactive H-bonded mesogenic unit and 5mol% of luminescent unit 2,7-bis[2-(4-hydroxyphenyl)-2-cyanoethyl]-9,9-dihexyl-9H-fluorene (CN-DHFP) was synthesized and characterized. The irradiation with LPUV light resulted in the induction of a small negative optical anisotropy (∆A) in the films due to the axis-selective photoreaction of the cinnamic acid group. After annealing the anisotropy was significantly enhanced. The enhanced reorientation direction of the mesogenic moieties and CN-DHFP groups was perpendicular to E of LPUV light. Polarized blue emission was obtained with polarization ratio of 1.6.

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Rheological properties, including the electrorheological effect, and the dielectric behaviors under steady shear flow are examined in the chiral smectic C (S_C^*) and the chiral nematic (N^*) phases of 4-n-octyloxyphenyl-4-(2"-methylbutyl) biphenyl-4'-carboxylate (8OBE). In the S_C^* phase the viscosity decreases linearly with increase in temperature, and above the S_C^*- N^* phase transition point TCN, it gradually decreases to lower values in the N^* phase. The flow in the S_C^* phase is non-Newtonian, which is in contrast to the Newtonian behavior in the N^* phase. The application of the electric field causes some increase in the viscosity in the S_C^* phase. These rheological and the simultaneously measured dielectric properties are discussed on the basis of the directional changes of the director and the smectic layer.

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Shape memory effects of uniaxially deformed smectic C* (SmC*) elastomers are investigated for two different types of crosslinker, namely a hydroquinone-type crosslinker and a rod-like crosslinker. Mesogens are allowed to tilt during the SmA-SmC* phase transformation in the elastomer synthesized with the hydroquinone-type crosslinker. As for the elastomer with the rod-like crosslinker, however, the smectic layers are tilted during the transformation, because the rod-like crosslinker is enough rigid to disturb mesogens in tilting. Since the shape change of the elastomer is coupled to the transformation of the molecular alignment, the elastomer synthesized with the hydroquinone-type crosslinker elongates with increasing temperature in SmC* because of the decrease of molecular tilt angle, while the sample length of the elastomer with the rod-like crosslinker is almost constant during the temperature range of SmC* despite the re-arrangement of layer structure. Both of the elastomers exhibit reversible shape change which respectively corresponds to reversible change of molecular alignment in a heating and cooling process within successive phase transitions between the isotropic phase and the smectic C phase.

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We had been reported that the transient response characteristics of the polymer stabilized bend (PSB) cell are deteriorated by polymer stabilization. This deterioration is caused by the increase of rotational viscosity and the decrease of flow velocity due to the changes of Leslie viscosities resulted from the polymer stabilization treatment. In our recent research, the transient response characteristics of the polymer stabilized splay (PSS) cell are ameliorated by the polymer stabilization treatment. In this research, the mechanism of the amelioration is investigated in detail.

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To prepare ionic conductive thin films with the aid of ionic liquid crystals, genimi ammonium complexes with tartrate ions as a counter ion, which are structurally simple compound consisting of ion pairs and aikyl chains, were synthesized and their thermotropic or lyotropic liquid-crystalline behavior was evaluated. The gemini ammonium complexes were found to show a columnar phase despite of non-disk-like molecules. It is significant that the ammonium complexes possess advantageous feature as thermotropic liquids crystals. Such liquid-crystalline property originates from the emergence of intermolecular hydrogen-bond interaction in the columns within the two-dimensional lattice. On the basis of the unique structural feature, we attempted to measure ionic conductivity of the columnar liquid-crystalline thin films.

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Electric field response of a cholesteric phase was investigated. When electric field was applied to the cholesteric phase of (S)-8-BP(X)MBs, it showed planer state to fan-shape state taransition. In this study, the effect of the chirality on the electric field response of the cholesteric phase was investigated. The (S)-8-BP(X)MBs with several enantiomer excess was prepared. The racemic form of (S)-8-BP(Cl)MB and (S)-8-BP(Cl)MB was mixed to investigate the effect of chirality.

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Dynamic behavior of liquid crystal molecules can be researched in terms of the elliptic polarized light measured with a time-resolved ellipsometry. In this study, the dynamic molecular motion of polymer-stabilized ferroelectric liquid crystal under the application of AC electric field has been investigated by using the ellipsometry, and then the effect of polymer stabilization onto the dynamics of ferroelectric liquid crystal is mentioned.

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We have proposed a laser manipulation system by using a liquid crystal (LC) optical device for controlling positions and rotation of trapped microscopic particles. The LC optical device with eight-divided circularly hole-patterned electrodes has variable-focusing, beam deflection and anamorphic lens functions for the transmitted laser beam. In this study, we evaluate about the operating characteristics of the LC optical device.

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We have reported alignment behaviors of nematic liquid crystals at micropatterned surface. The patterns were formed by stripes of alternating planar and homeotropic anchorings. There are two cases where the preferred azimuthal alignment on the planar stripes is either parallel or perpendicular to the stripes. In this study, we will discuss alignment of nematic liquid crystals at a micropatterned surface with alternating planar (in which the preferred azimuthal alignment on the planar stripes is parallel to the stripes) and homeotropic anchorings.

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In the present study, we propose MC simulation that takes interface phenomena between liquid crystal and substrate into consideration.We use rigid model molecules of liquid crystal and substrate.Interface is generated using potential field that induces decomposition of molecules.

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A nematic liquid crystal membrane was fabricated in distilled water successfully and an alternating sinusoidal voltage was applied to it. An electrooptic response of the membrane was measured using a crossed polarizing optical system, and it was found that there were different responses in the same film. One place has the dominant 2nd harmonics component at low frequency. Another place has the fundamental or the dominant 2nd harmonics component as dominant in whole frequency range. In this study, a distribution of the electrooptic characteristics in the film has been investigated.

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