We have investigated the new type of antiferroelectric liquid crystal mixtures with I-N-A-C phase transition. They were prepared by mixing chiral pyranose compounds and achiral liquid crystal materials having I-N-A-C phase transition. In the microscopic observation. they showed excellent molecular alignment in SmC_A^* phase due to the existence of nematic phase. We also observed the thresholdless V-shaped switching at the specific content of chiral pyranose compounds.

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In order to study the steric effect around chiral carbon to liquid crystallinity of antiferroelectric liquid crystalline materials, we designed and synthesized liquid crystal compounds having a 2-pentylcyclopentyl ester group. The trans-2-pentylcyclopentyl ester type compound exhibited stable antiferroelectric chiral smectic C phase, whereas the cis-2-pentylcyclopentyl ester type compound exhibited unidentified smectic phase.

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In order to study the steric effect around chiral carbon to liquid crystallinity of antiferroelectric liquid crystalline materials, we designed and synthesized liquid crystal compounds having a 1,2- or 1,3-dimethylheptyl ester group. Although the anti-1,2-dimethylheptyl ester type compound exhibited SmA, SmC^* and SmC_A^* phases in a way similar to 1-methylheptyl ester type compound, the syn-1,2- and 1,3-dimethylheptyl ester type compounds showed SmA artd SmC_A^* phases.

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Ionic liquid crystals with a piperidinium skeleton were synthesized and their thermal and liquid crystalline properties were examined. The tonic liquid crystals having a tertiary ammonium unit formed an enantiotropic smectic A phase and displayed a glass transition. The ionic liquid crystals having a quatemary ammonium unit showed glass-smectic A phase and smectic A - isotropic phase transitions. In the glass phases, the smectic A arrangements remained unaltered on cooling from the smectic A phase.

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Binary mixtures of neunatic 5CB with some kind of mton-mesomorphic solutes were found to cause the increase in nematic-isotropic transition temperature, contrary to usually observed decrease. "Unusual" solutes found in this work all had active hydrogen which can act as hydrogen bond donor. Admixing of methyl or ethyl substituted compounds of above solutes resulted in usual depression of transition temperature. "Unusual" increase in clearing temperature were atributed to the hydrogen bonding interaction between 5CB and solutes. The thermal effects of hydrogen bonding interaction between 5CB and various non-mesomorphic solutes were studied in detail.

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Microcanonical features of a liquid crystal molecule reflect on its macrocanonical properties. The critical temperature of the liquid crystal largely depends on its exact size and character of the substructure of a liquid crystal molecule. The series of liquid crystal molecules which have the same skeleton were investigated by the vibrational Raman spectroscopy. T'he changes of the polarizabilities of the each vibrational line are recorded as the function of temperature in the process of the phase transition. The function of the polarizability for the each vibrational line exhibits the characteristic change in the process of the phase transition. The lines which are due to the normal coordinate having the specific vector against the molecular axis show the irregular dependence on the increasing of temperature in the process of the phase transition.

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In this study, we synthesized a homologous series of cholesteryl-ω-hydrofluoroalkylthionate (SCHFA) [C₂₇H₄₅SC(O)(CF₂-CF₂)nH N=:1〜4], and investigated their mesomorphic phase transitions. In SCHFA, a liquid crystalline phase was found only for the n=4 homologues

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This study reports phase transitions of monomers and polymers in (fluoroalkyl α-substituted acrylates)s. We found that the monomers with long side chains and poly(fluoroalkyl α-fluoroacrylates) exhibited smectic liquid crystals.

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A series of 2-(4-n-alkyloxyplaenyl)-5-(4-methylphenyl)pyridine(CH₃C₆H₄C₅H₅NC₆H₄OC_nH_2n+1, n=1-10)(APMPP) was synthesized and their mesogenicity was studied using polarizing microscope observation and DSC measurement. The polymorphism of stmectic phases was observed in which APMPP homologues of n>4, where nematic phase was found in all the APMPP.

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We have investigated phase transition phenomena in the complex system which consists of the lyotropic liquid crystal and the latex colloidal particles. When the diameter of the doped latex particles is comparable to the microscopic characteristic length of the liquid crystalline order, defects of the liquid crystals are excited around the latex particles. This elastic coupling of the liquid crystalline order and the doped particles could produce the new type of the long-range attractive interparticle interaction. Thus, the colloid particle stability must be controlled by the microscopic structure of the liquid crystal medium. On the other hand, since the elastic distortion energy around the particles and the entropy of the particles contribute the total free energy of the complex system, the Lamellar-Sponge phase transition also be influenced by the diameter and the concentration of the doped latex particles.

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The shear effects to the L_α-L₃ phase transition was investigated in the hyper-swollen lyotropic liquid crystal. We experimentally confirmed that the shear induced L₃ to L_α phase transition takes place, by using the static light scattering under oscillatory shear flow. The dynamic phase diagram was also constructed based on the quantitative measurement of the peak intensity and the peak wave-length of the Bragg reflection. It is emphasized that the phase transition order is modified from the first order to continuous under high shear regime. The fundamental origin of the shear induced phase transition was proposed that the shear flow tears off the passage of the membrane, due to the coupling between the shear flow and the three-dimensional inter-connected structure of the sponge phase.

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We measured the fluctuations in the lyotropic liquid crystal lamellar (L_α) phase and the sponge (L₃) phase in a dilute region of surfactant concentration by the dynamic light scattering technique. We observed the concentration fluctuation induced by the thermal undulation of layers in the L_α phase and obtained the dependence of the effective rigidity k_c of layers can the repeat distance d, which reflected the fluctuation-induced layer softening. Further, two kinds of fluctuation modes were observed in the L₃ phase.

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Monosubstituted ferrocene derivatives, [4-[ω-(cholesteryloxycarbonyl)alkoxycarbonyl]phenyl]ferrocene (CAPF-n)(n is the carbon number of the methylene chain, n = 1〜11,15) have been synthesized. Some of them (CAPF-2, 4, 6, 8, 9, 10, 11, and 15) exhibited liquid crystallinity. In this study, the crystal and molecular structure of CAPF-10 was determined by X-ray diffraction method in order to discuss exactly the structure of liquid crystalline phase. The crystallographic data are as follows; C₅₅H₇₈O₄Fe, M = 859.07, monoclinic, space group C2, a = 73.82(4), B = 5.884(1), c = 11.044(4) Å,β = 94.36(4)°,V = 4782.8(9) Å^3, Dc = 1.193 gcm^-3, λ(MoK) = 0.71069Å,μ = 3.59 cm^-1, F(000) = 1864.00, Z = 4.

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The dynamic viscoelastic properties were studied for the monosubstituted ferrocene derivatives containing cholesteryl group as a mesogenic one, [4-[ω-(cholesteryloxycarbonyl)hexyloxycarbonyl]phenyl]ferrocene, synthesized in our laboratory. In the heating process, an abrupt drop of the storage modulus(G') was not observed around the clearing temperature estimated from DSC. Even in the liquid state above the clearing point, the storage modulus(G') decreased successively with increasing temperature, Such behavior is different from the general behavior of liquid crystals. The viscoelastic results under different heat treatments suggest that the liquid state is not isotropic completely.

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Monosubstituted ferrocene derivatives, [4-ω-[4-(4-methoxyphenoxycarbonyl)phenoxycarbonyl] alkoxycarbonyl] phenyl]ferrocene (MAPF-n)(n is the number of carbon atoms in the methylene chain, n = 1〜7, 10 and 11) have been synthesized in our laboratory. The liquid crystallinity of these compounds was investigated by dufferential scanning calorimetry and polarizing microscopy observations. The result suggested that four kinds of MAPF-n (n = 4, 6, 10 and 11) exhibit liquid crystallinity. In this study, dielectric measurements were carried out in order to discuss molecular motions. These compounds showed two clearly separated relaxation processes above glass transition. Phenomenological analyses of these relaxation were made to establish activation energies of relaxation processes and parameters characterizing the broadness of the relaxation time distribution.

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The two homologous series of monosubstituted (APF-n)(n is the number of carbon atoms in the alkyl group) and disubstituted ferrocene derivatives (bAPF-n), which are shown in Fig.1, have been prepared and the phase transition of these compounds have been studied by the differential scanning calorimeter (DSC) and the polarizing microscope. In this study, APF-n and bAPF-n were compared from view points of an appearance of the phase transition. All of the APF-n have exhibited no liquid crystal phase. The APF-n (n=4,6,8,9) just have exhibited crystal-crystal phase transitions. On the other hand, all disubstituted ferrocene derivatives have shown the liquid crystal phase. These liquid crystal phases are considered a smectic phase.

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We propose a question: " If liquid crystal phase intrinsically possesses characteristics of machinery, then how it behaves? We have considered critical behaviors of liquid crystals as machinery systems. As means for unified treatment of the critical transition. Bragg-William's-like modelins for molecular-terminals position array are adopted and mean field-mechanical analysis are applied. We have established following predictions: 1) Smectic B crystal phase as rigid rotor posses transition temperature dependence proportional to its 4th-power of molecular length. 2) Necessary conditions for occurrence of hexatic B phases that can predict molecular structural requirement for it. 3) Necessary conditions and predictable molecular designs for tilted phases.

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A frequency dependency of dielectric anisotropy (Δ ε) of no CN Liquid Crystal materials has been investigated. Δ ε_r(=Δ ε (100kHz)/Δ ε (1kHz)) strongly depends on a chemical structure. Δ ε decreases largely at high frequency in high T_NI, flexible bond and except F atom (O, Cl) included materials. A viscosity increases at high T_NI LC, but a relation between Δ ε_r and rotational viscosity is not clear in this study. AM-LCD mixture, which Δ ε has very small frequency dependency characteristic, can be designed with large Δ ε_r single materials.

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Pulsed field gradient spin echo NMR spectroscopy has been developed to measure anisotropic self-diffusion coefficient. By using a rotatable quadrupole coil and a magic angle orientation technique, the anisotropic self-diffusion coefficients were measured in the smectic A phases of a reentrant liquid crystal CBOBP, 4-cyanobenzoyloxy(4-octyl-benzoyloxy)-p-phenylene. The diffusion anisotropy showed different behaviors between smectic Ad and smectic A1 phases.

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Viscosity measurement of smectic liquid crystal has been performed using a shear horizontal (SH) mode device which has two acoustic wave channels. The liquid crystal cell is mounted on one channel and the other channel is used as a reference. The upper substrate of the liquid crystal cell is a glass plate coated with polyimide which is rubbed to achieve unidirectional homogeneous alignment. The acoustic phase delay difference between two output signals propagating the channels has been measured as a function of temperature. The displacement of SH mode is perpendicular to the propagation direction. The liquid crystal used in the experiment have several phases in the measured temperature range from room temperature to isotropic phase. Two viscosity components, parallel and perpendicular to the alignment direction, have been discussed in some liquid crystalline phases.

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Recently, the liquid crystalline elastomers containing the quaterphenyl groups (DHQ polymer) have been investigated by means of X-ray, differntial scanning calorimetric, dielectric and dynamical mechanical measurements. The DHQ polymer was found to show two phase transition near 7℃ and about 47℃. In this work, X-ray diffraction experiment was carried out in order to confirm the structure and phase transition. We performed a detailed structural study of the DHQ polymer.

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The relation between viewing angle characteristics of TN-LCDs and liquid crystal (LC) aligning properties was studied. Three type TN-LCDs with different surface alignments under the retardation condition of 2nd minimum were prepared. Cells of type 1 and 2 are filled with a nematic and a chiral nematic (cell thickness / chiral pitch=0.25) LCs respectively, although both of them are constructed with a pair of rubbed and MOLCA-treated substrates. By choosing the strength of magnetic fields, the LC direction ordering on the substrates treated by MOLCA is controllable. From conoscopic observation of type 1,2 and conventional rubbing TN-LCD, improvement of the viewing angle characteristics could be recognized.

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We investisated the viewins angle characteristics of TN-LCD calculatins the polarization using Poincare sphere. We clarified (1) The reason for the difference between viewins angle characteristics for e-mode and o-mode is that the azimuth direction of the polarizers changes in oblique viewing. In upper-right, upper-left, lower-right, and lower-left viewing, as the polarizers' angle does not chanse, the viewing angle characteristic for e-mode and o-mode are the same. (2) The viewing angle characteristic in normally - white mode is symmetrical, but that in normally - black mode is asymmetrical. One reason is that the normally - white mode has rotation symmetry in alignment and polarizers but normally - black mode does not. Another reason is that the azimuth direction of polarizers deviates from the original position set for the normal direction or from the 90-270° line in the oblique viewing.

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A director arrangement of the ASM(Axially Symmetric aligned Micro cell) mode has been investigated by a simulation method. In the result, we have found out a director arrangement model which indicates a similar schlieren pattern of an actual ASM cell. According to the model, the ASM mode consists of the micro TN(Twisted Nematic) columns which are located that the focus of its director at the mid plane make a concentric circle about the center of a pixel, and as the radius of circule gets larger, circular shape is distorted to fit the shape of polymer wall.

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An interpretation of the displacement current against triangular wave voltage applied to an LC cell is proposed. Constant current against voltage curve corresponds to the charging and discharging current of an LC cell capacity. Linear current against voltage curve corresponds to the ionic conductive current originated in ionic impurities in an LC cell. And nonlinear current which showed diffusion-controlling property is interpreted as the oxidation-reduction current of specific ionic impurities. By applying this method to asymmetric LC cells, we can understand the origin of image printing.

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In order to prevent parallax, or decrease of resolution, in reflective LCDs, the diffusing reflector must be placed inside of the LC-cell, just behind of the liquid crystal layer, and near polarizer must be removed. In such single-polarizer-LCD, effect of the phase difference and depolarization of reflected light by diffusing reflector was evaluated. It is confirmed from the results that these problems were not severe for practical application of the LCDs.

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An optimization method based on measurements is proposed for achieving black and white representation in reflective STN-LCDs with single polarizers. By experimental applications of this method, good black and white representation with the maximum contrast ratio of 4.9, reflectance of 22% and good achromaticities has been achieved.

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Recently,we have proposed a novel STN-LCD with excellent pressure resistance, named Polymer-Matrix(PM)-STN-LCD in which polymer walls enclose each pixel by using polymer-liquid crystal phase separation method. In this paper, we discribe the electro-optical propertices and pressure resistance of PM-STN-LCDs. And we have achieved the multiplexed STN-LCD with PM structure.

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A new pitch measurement method of chiral nematic liquid crystal has been studied. Cell gaps near disclination lines are calculated from measured spectrum of Canos wedge cell placed between crossed polarizers. The chiral pitch can be obtained correctly from the difference of the cell gaps.

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Recently, there is an active trend to put STN LCD into practical use of a large display like a monitor. In case of conventional STN LCD developed so far, however, the narrow viewing angle is the most serious disadvantage, critically unacceptable to monitor. To improve the viewing angle characteristics of STN LCD, we try to adapt two domains method using the reverse rubbing treatment. we will report this result.

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Recently the authers proposed a novel type of LCD which is based on the fieldinduced reversible transition from a SIN state with the twisted angle Φ to a RTN state with the twisted angle Φ-2π and vice versa. In this study, it is experimentally investigated how the doping of a UV curable liquid crystalline polymer into the chiral nematic LC material affect the electro-optical properties of the type of LCD mentioned above. As the results, the necessity of the application of holding voltage was removed and the transient characteristics was improved.

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The DC-cell transient properties and the gate-pixel coupling effect in TFT-LCDs are modeled so that we can analyze the dynamic interaction between LC-cell and TFT which can not be analyzed adequately by conventional models. Small vibration analysis and numerical analysis for the DC and 30Hz component of transmittance have been done using the models. The results agree with corresponding measurements, illustrating the validity of the models and the importance of the dynamic interaction between LC-cell and TFT.

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We have proposed a new reflective LCD (R-OCB cell) composed of a hybrid-aligned nematic LC-layer, a biaxial-retardation film, a mirror electrode and the light scattering film. This LCD has many features , while it had a problem of light leakage at dark state. In this paper we describe optimum design condition to get an achromatic color by designing of dispersion of LC and retardation film.

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We proposed Trench Cell LCD, a novel structure of LCD cell. The conventional LCD cell has suffered from the dilemma that the electrode gap must be shortened to strengthen the electric field and must be elongated to emphasize the optical reflectivity and contrast. The Trench Cell LCD resolves this dilemma, as its electric field falls at right angles with its optical path. We have carried out the Computer simulations of the optical action in the Trench Cell LCD and the conventional one. The optical characteristics of the Trench Cell LCD a result of the simulation, have been compared with those of the conventional cell.

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Hybrid-aligned nematic liquid crystal displays (HAN-LCDs) are known to have the device peformance of fast response speed and low driving voltage. In this paper, we have tried to improve the viewing angle characteristics of HAN-LCDs by using optical compensation films. The study is performed by doing computer simulation of the device. The result show that the use of optical compensation films for widering the viewing angle performace is very successful to keep a wide viewing range of the black level and thus, the good viewing angle characteristics is obtained.

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Reflective liquid crystal displays (LCDs) are attractive for their light weight and low power consumption. Highly-twisted nametic LC cells have a hysteresis in the EO performace. A bistable-LCD, which was reported by Berreman et al., utilize this hysteresis effect. It has an advantage of low cost driving without using active elements. In this paper, we study theoretically and experimentally the bistable reflective GH LCDs.

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Dielectric relaxation was measured for a ferroelectric liquid crystalline side-chain polymer LCP1 to investigate the molecular dynamics of side-chain. The measurement was performed on two specimens; aligned and non-aligned cells.

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We synthesized ferroelectric liquid crystalline polyacetylene derivatives with chiroptical liquid crystalline group in the side chain. Polymerizations were performed by Mo- and Rh-based catalysts. Molecular structures were confirmed by means of IR, NMR, UV-Vis, and GPC. Liquid crystallinity was examined by DSC and polarizing optical microscope.

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The polymeric ferroelectric liquid crystals with two chiral groups, one on each side of the core, show large spontaneous polarization. We prepared ferroelectric liquid crystal copolymers containing the dichiral liquid crystal and a nonchiral liquid crystal. Copolymerization resulted in a chiral smectic C phase existing over a wide range of temperatures, including room temperature. Mixing the copolymers with low-molecular-weight liquid crystals further decreased the viscosity and improved the response time. The mixture responded to an electric field within a hundred milliseconds at room temperature.

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Temperature dependence of smectic layer thickness in antiferroelectric liquid crystals has been investigated. We classified into three types of temperature dependence of layer thickness. Small change of layer thickness made liquid crystal mixtures have small amount of zig-zag defects. As a result, the alignment in the first stage nearly remains unchanged in thermal shock atmosphere.

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Reflection ellipsometry is applied to characterize the molecular orientation of rubbed polyimide films for LCDs. Larger anisotropic polarization is observed in reflected light than in retardation of transmitted light. Reflection ellipsometry has at most 30 times higher sensitivity than retardation measurement. Effect of rubbing-strength to polyimide film is observed with reflection ellipsometry. It is clarified by analyzing the polarization of reflected light that rubbed polyimide film is composed of a molecular-oriented upper layer and an isotropic lower layer. In my strongest rubbed film, the thickness and tilt angle of principal dielectric axis of the upper layer were determined to be about 13nm and 40°, respectively. Observation indicates clear dependence of tilt angle on rubbing strength. Rubbing-strength dependence was not observed in thickness of molecular orienting layer.

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Most of nematic liquid crystals (NLCs) align parallel to the rubbing direction on poly-hydroxyethyl methacrylate (pHEMA), except those having a bicyclohexane core which align perpendicular to the rubbed direction. Alignment directions of NLC with the bicyclohexane core are investigated on various rubbed polymers. The relation between the conformation of side chain molecules and the aligning mechanism of NLCs is discussed.

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It was found that the N-I transition temperature of nematic liquid crystals decreases when it is measured close to structures grown of the glass substrates and which were covered by rubbed alignment layers. It is suggested that the decrease is due to a change in the splay strain of the liquid crystal molecule orientation close to these structuares which result in lower transition energy.

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Adsorptive strength and stabilities of liquid crystalline (LC) adsorbates prepared by m-MOLCA (modified Magnetically Oriented LC Adsorbate Method by Utilizing Solvent Evaporation) were studied. Thicker LC adsorbate layers more than necessary are not desirable for an effective aligning technique. Removal of the surplus LC adsorbate by spinning at an isotropic temperature and washing in the solvent enabled the good LC alignment. From the experimental results, it became clear that the coating polymer material and adapting time of LC adsorbate played an important role.

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In-plane field induced liquid crystal alignment properties are observed on several polymer after applying and removing the voltage in the homogeneous cell where the flow direction of the liquid crystal is different from the in-plane field direction. The alignment direction changes on some polymer, ex. PVA, with a hydroxyl group in their side chain molecules. It does not change on a PI or rubbed polymer surfaces. Polymers which are used as a polymer dispersed liquid crystal cell are also described and discussed about their memory effects.

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Free-standing (FS) ferroelectric and polymeric ferroelectric liquid crystal films have been fabricated successfully. Electro-optic measurements of FS films have been carried out. Molecular reorientation dynamics due to applied field reversll in FS ferroelectric and polymeric ferroelectric liquid crystal films has been studied using a polarizing micro scope. Many disclination lines due to locational deference of rotation sense of molecular reorientation have been observed.

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Peculiar surface properties of poly(L-glutamic acid)(PLGA) assentblies on water were demonstrated, in particular, in terms of their specific corformation and interactions with guest molecules. Two types of PLGA amphiphiles were prepared: one of them is a diblock-polymer and another one is a triblock-polymer. These PLGA-functionalized monolayers were characterized by measuring π-A isotrherms, CD and FTIR spectroscopy, and were also examined by estimating the interaction with α-amino acids.

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In the smectic C-like phase of an azobenzene derivative Langmuir monolayer, spontaneous formation of variety of modulated structures such as stripes and spirals takes place. Particularly notable finding is that orientational point defects with an extremely large strength are stable in contrast to the almost complete absence of higher order point defects in bulk liquid crystals. This paper discusses the origin of the stability in terms of an extended 2D Frank continuum theory taking account of the surface specific elastic term.

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Within the sharp interface approximation, we derive microscopic expressions for the surface contributions to bend and splay elastic deformations on the basis of the Mair-Saupe type molecular statistical theory. Using this microscopic perspective, we are able to investigate quantitatively the nature of sub-surface director deformations predicted by the phenomenological continuum theory.

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Reflective liquid crystal display (LCD) with guest-host (GH)mode and quarter-wave plate was proposed by Coles. We have modefied this mode by fabricating the wave plate inside the cell to obtain high resolution and taking homeotropic alignment to obtain high brightness. This LCD has gray scale capability, high reflectance of more than 60% with contrast of 5 and low drive voltage of 10V.

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