A phase diagram of nCB/9CB (n=4-7) system was constructed using DSC and polarizing optical microscopy. Nematic, smectic A, and reentrant nematic phases appeared in the systems, similarly to phase behavior of nCB/8CB (n=0-6) systems, which we previously reported. Distinction was recognized for the phase boundaries between nematic and smectic A phases of even and odd n of nCB. The odd-even effect in binary nCB systems is discussed.

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In general, the volume ratio between the hydrophobic and hydrophilic parts of the amphiphile is important to show lyotropic phases with lamellar, micellar or vesicular structures. In the case of nonionic polyethylene glycol monoalkyl ether (C_mE_n: m is the alkyl carbon number, and n is the number of the oxyethylene units), the ratio m/n determines the phase transition behaviors; hyperswollen lyotropic lamellar phases appear when m/n is in a certain range (2.4〜4). We examined whether aqueous C₁₂E₆ solution, which does not show hyperswollen lamellar phases intrinsically, added toluene shows a hyperswollen lamellar phase. Instead of toluene, the addition of styrene to a C₁₂E₆ solution also induces a hyperswollen lamellar phase. Thus, polymer and carbon nanosheets from the styrene can be synthesized in the hyperswollen lamellar phase. Furthermore, we found that the temperature range of the hyperswollen lamellar phase can be controlled by the addition of glycerol.

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Study on molecular orientation changes by phase transition is important to reveal the stability mechanism of chiral nematic liquid crystal (N^*LC) exhibiting blue phases (BPs) and developing of new generation LC devices as well. In this study, the polarized microscopic FT-IR spectroscopy has been applied for study on molecular orientation of N^*LC by the phase transition. The vertical and in-plane molecular orientation change of NLC molecules have been determined by band intensity ratio CN/CH_2 of non-polarized IR spectra and band intensity of CN stretching mode of polarized IR spectra, respectively. In conclusion, the lattice of BP I is more likely to affect the molecular orientation change of N^*LC on cooling process.

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We calculate the confocal microscope images of cholesteric blue phases using the combination of plane-wave expansions and finite-difference discretizations in solving the Maxwell equations for light propagation and reflection. Although the confocal images along the depth direction are not simple repetitions along the depth direction, for a BP I sample of lattice spacing α whose [110] plane is parallel to the cell surface, the variations of the intensity of confocal images along the depth direction exhibit oscillations whose periodicity is approximately equal to √<2>α that agrees with that of blue phase ordering.

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Recently, we reported "discontinuous anchoring transition" in liquid crystal cells using a specific combination of LC- and surface-coating materials, that is, nematic liquid crystal (CCN-47) and perfluoropolymer (CYTOP, Asahi Glass Co.). This phenomenon observed as an abrupt director change between homeotropic and planar states by cooling or heating, was investigated by means of high-resolution differential scanning calorimetry and grazing-incidence x-ray diffraction, as well as careful polarization microscopy. These experiments revealed; (1) different molecular orientations, homeotropic and planar at the surfaces, have different thermodynamic free energies; (2) the discontinuous anchoring transition occurs through the formation of quasismectic layers parallel to surfaces in the nematic phase.

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An easy axis of rubbed polymers with aromatic side-chains depends on liquid crystal (LC) materials. MBBA and some LCs which aligns parallel to the rubbing direction (perpendicular to the slow axis) and other LCs aligning perpendicular to the rubbing direction are mixed. A relationship between alignment direction and mixture ratio of two LCs on the rubbed poly(4-vinyl pyridine) are investigated. An anchoring strength is also measured as a function of the mixture ratio. It is suggested that LC having a polar group is preferentially adsorb to alignment film.

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We have investigated the effect of alkyl-amine vapor treatment on pretilt angle generation by photo-alignment films of polyimide containing azobenzene in the backbone structure (Azo-PI). By performing alkyl-amine vapor treatment in preparing photo-alignment Azo-PI layers, the controllable range of the pretilt angle was extended at least up to 38° without appearance of threadlike disclination loops. We found that such a high pretilt angle was induced by the photo-alignment layers with a high inclination angle and narrow orientation distribution of the Azo-PI backbone structure in the out-of-plane direction.

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We report the electric field response mechanism of anisotropic liquid crystal (LC) micro-particles in a nematic LC host. Square-shaped particles with unidirectional molecular alignment were fabricated via twophoton excited direct laser writing, dispersed in a low-molecular-weight nematic host, and driven by an electric field applied in the in-plane direction of the cell. The constructed theoretical model could be used to reproduce fits to the experimentally demonstrated, fast and reversible switching of LC micro-particles. Down-sizing of the particle size and the use of a low viscosity host is key to achieving a fast response.

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Free-standing films composed of chiral liquid crystals are known to exhibit the unidirectional director rotation under transmembrane mass flow. The dynamics is well described by Leslie's phenomenological equation, which predicts the inverse process of mass transports driven by the director rotation. In this report, we investigated this inverse effect. Applying a rotating E-field to the film that should drive the unidirectional rotation of the c-director, we simultaneously measured the transported gas through the film.

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The smectic CA phase of main-chain BB-5(3-Me) polyester was examined for the orientation under large amplitude oscillatory shear flows. Although the layer normal aligned to the neutral direction at frequencies in the investigated range, the c-director direction was strongly dependent on the frequency. At frequencies ranging from 1-10 Hz, the c-director aligned to the velocity direction, and otherwise, it aligned to the velocity gradient direction.

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We have introduced slippery interfaces on the homeotropic SmC* liquid crystals in IPS cell by the phase separated liquid droplets. Light induced phase separation in the azo dye doped liquid crystal well demonstrated the roles of the slippy interface in comparison with before and after UV illumination. We success to realize the drastic reduction of the driving voltage (<1〜2V/μm) keeping the response time is fully fast in comparison with the original material (〜20μsec). Using the short pitch SmC* material, almost complete black state can be achieved without large increase of the threshold voltage. Since the polar distribution of C-director can be generated under electric field, we can accelerate the speed of recovery to the black state (〜20μsec) by applying a short negative voltage pulse, nevertheless the slow helix deformation mode (〜1msec) is produced by the large electric field, which affect to the degeneration of the response against switch on/off voltage.

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Recently, in the system where the droplets formed by the cholesteric liquid crystal are dispersed in the isotropic medium, we found double twisted structure is stabilized. As the chirality of the system or the size of the droplets increases, the structure transits from the double twisted into the single helix structure. Moreover, calculating the elastic free energy in the system, we succeeded in explaining the structural transition described above theoretically.

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Making isotropic droplets in the cholesteric (Ch) liquid crystal, we found spiral textures appear on the interface between the Ch liquid crystal and the droplets. Moreover, applying temperature gradient to this system, we found the texture rotates. To clarify the origin of this heat-driven rotation, we analyzed the flow field in the system. As a result, it was found convection is induced in the droplet when temperature gradient is applied; thus, we concluded this convection is the physical origin of the heat-driven rotation.

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Cholesteric LC droplets dispersed in isotropic phase are known to exhibit a unidirectional barycentric rotation under a temperature gradient. Theoretically, Onsager relation predicts such interesting inverse process that the rotation of cholesteric droplets should transport a heat along the rotational axis. We tried to cause the heat current by mechanically rotating the cholesteric droplets in the isotropic phase. Although a convincing result has not been obtained, we noticed some difference between the cholesteric droplets and nematic ones.

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The orientational fluctuation of SmC Langmuir monolayers was studied by means of polarized light scattering. We used several kinds of hydrogel solutions and examined how the gelation of the subphase should influence the viscoelastic properties of the monolayers. The director fluctuation depended on both the LC compounds and the hydrogels, and was considerably suppressed by the subphase gelation. The result can be ascribed to the adsorption of the gel molecules onto the LC monolayers followed by the formation of the local gel networks at the interface.

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It is generally difficult to rotate the nematic director by applying a weak external field because nematic liquid crystal molecules are anchored at a solid substrate. We proposed and fabricated the "Slippery" interface, at which nematic director was not anchored and rotated freely. In our system, we mixed liquid crystal with impurities which favored a solid substrate. The impurities decrease the orientational order of liquid crystal near the substrate, and a thin isotropic wetting layer is formed at the substrate as a result. At the isotropic wetting layer, the anchoring of liquid crystal is very weak, and hence the director could easily rotates by applying a very weak external field.

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Topological defects, or disclinations in nematic liquid crystals, occur where the orientation of the director is discontinuous. Investigating means of controlling of the shape and topology of disclinations has recently attracted interest owing to their potential for applications; however, most studies to date have focused on systems in which colloidal particles were introduced or complex-shaped substrates were used, and hence had limited tunability. Here we demonstrate the generation and electric field control of disclinations based on surface alignment control in a nematic liquid crystal slab. By imprinting easy axis distributions containing singular points on substrates in contact with the liquid crystal, we show that disclinations with controlled numbers and shapes can be induced in the bulk, and that they can be reconfigured by voltages as low as 1.5 V.

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In the bicontinuous cubic (Cub_bi) phase formed by rodlike molecules, lateral thermal expansion of the terminal alkyl chains and resulting tapered molecular shape is a major driving force for the formation. In this view, introduction of oligodimethyl siloxane segments at the termini of the alkyl tails would be an effective methodology for obtaining the Cub_bi phase at lower temperatures. Actually, the method was found to successfully stabilize the Cub_bi phase and expand the temperature range toward low temperatures. In the case of a disiloxane-terminated molecule, however, the lattice dimension of the Cub_bi phase around room temperature does not depend solely on temperature but was found to show a range of values probably depending upon the previous thermal history. In this presentation, we will attempt to explain such complicated sort of "fluctuation" in the structural periodicity in terms of molecular motions and phase separation between siloxane and alkyl segments.

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Non-peripherally alkylated liquid crystalline metal-free phthalocyanines (Pc) exhibit good carrier transport properties in their columnar phases at high temperature. However, they crystallize at room temperature and their solubilities are insufficient to forms thin films by a solution process. In this study, we synthesized nikel Pc complexes bearing siloxane moieties. These compounds exhibit columnar phases at room temperature in spite of their bulky siloxane moieties, through nano-segregation between π conjugated cores and siloxane moieties. Moreover these have high solubilities in n-hexane and one of these compounds exhibits ambipolar carrier transport at room temperature.

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The blend of liquid crystalline octahexylphthalocyanine (np-C6PcH₂) and octahexyltetrabenzoporphyrin (np-C6TBPH₂) was studied on the miscibility in mesophase and their charge transport properties. Though C6PcH₂ (showing pseudo Col_h mesophase) should be immiscible to C6TBPH₂ (exbiting Col_h and Col_r phases) for the mesophases, an ambiguous situation between pseudo-Col_h and Col_r phases was seen. This indicates that these two columnar mesophases have a similar molecular order and these can be formed with a small modification of 2D arrangement of disc-shaped molecules. The carrier mobility was determined by TOF technique and the mobilities of both hole and electron are decreased in the mixtures probably due to the different energetic levels of HOMO/LUMO. The repetitive heating and cooling cycles around the clearing point give a different behavior in charge transport from that of the blend of octadecylphthalocyanine and its Zn complex.

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We evaluated hole mobilities of a dibenzophenazine derivative and a barbituric acid derivative Ni complex in columnar phases by time of flight method, evaluated values were 〜4×10^-3 and 〜8×10^-4 cm²V^-1s^-1, respectively. We analyzed relationship between the mobility and the structure and molecular packing by fitting the temperature dependence of the mobilities in Gaussian disordered model. Electric field and temperature dependencies of mobilities were consistent with the theoretical equation. The columnar phases have a smaller spatial disorder parameter than that of amorphous materials and some disordered columnar phases. This small value of the parameter probably comes from trimerization, nickel ligand field.

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A series of smectic liquid crystals of benzo[c]cinnoline derivatives are efficiently prepared and their mesomorphic behaviors are investigated by POM, DSC and XRD in detail. Dialkylated derivatives 10-Ph-BC-Ph-10 and 12-Ph-BC-8 facilitate highly ordered smectic mesophases, while the monoalkylated ones only show low-ordered mesophases. The formation of a bilayer structure appears for asymmetric compound Ph-BC-8. All these compounds exhibit relatively low LUMO levels among -3.14eV〜-3.18eV, indicating possible n-type conduction.

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Recently, we have reported an anomalous photovoltaic effect in chiral smectic C phases of the ferroelectric fluorophenylterthiophene derivatives. Now, we focus on the mechanism of the effect in the LC phases and improvement of the conversion efficiency. On the hypothesis that the anomalous effect is affected by the ferroelectricity and photoconductivity, the enhancement of the effect is expected by increasing the spontaneous polarization and the carrier mobility of the materials. In this study, some fluorophenylterthiophene derivatives have been synthesized. We have characterized the LC property, the photoconductivity and the spontaneous polarization of these compounds. In this presentation, we will discuss on the correlation between the ferroelectricity and the sample thickness.

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Charge transport properties in organic semiconductor are a consequence of averaging of electron charge transfer, electronic states and their disorders controlled by structural order parameters and thermal fluctuation of their molecules. In this study, we have investigated a relationship between charge mobility and the degree of a structural order of molecules in molecular aggregates, and related order parameters to electronic transport properties, using molecular dynamics simulations and quantum chemical calculation of some particular molecules. From the viewpoint of order parameters in liquid crystals, we propose concepts how the liquid crystalline order parameters affect the electronic charge transport in ordered organic semiconductors, and we examine the charge transport mechanism of organic semiconductor exhibiting liquid crystalline phase.

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A dimer bearing two phenylterthiophene parts linked by a chiral moiety with a minimized molecular volume has been synthesized. This chiral dimer exhibits a chiral nematic phase and its helical structure can be fixed by cooling rapidly. The reflection band can be tuned between near ultraviolet and infrared wavelength by mixing enantiomers of the dimer or changing the temperature. Circularly polarized light emission has been observed in the chiral nematic phase. In fluidic chiral nematic phase, circularly polarized photoluminescence can be switched to non-polarized state reversibly by the application of the electric field.

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A new method has been developed to fabricate a parallel-aligned polycrystalline thin film via liquid crystal. By using a top-coated film of water-soluble polymer, i.e., polyalcohol (PVA), the alignment of spin-coated liquid crystal thin film was successfully re-oriented from "perpendicular" to "parallel" orientation. Parallel-aligned Polycrystalline thin film as thin as 50nm could be easily processed while maintained good morphology. Our method will lead to a possible application of parallel-oriented organic semiconductor polycrystalline thin films, which can be hardly achieved with convention non-liquid crystalline organic semiconductor materials.

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A binary system of a polymer liquid crystal and a small molecular liquid crystal is expected to give a polymer-dispersed system in which the mesogenic compound makes appropriate domains for efficient charge transport. In this work, small molecular liquid crystalline semiconductor, 2,6-bis(5-nonylchieno)naphthalene (9TNAT9) which has highly ordered mesophase exhibiting high hole mobility in the order of 10^-1 cm²V^-1s^-1, 1) and a polymer liquid crystalline semiconductor, regioregular poly(3-hexyl)thiophene (P3HT) were blended to see the phase separation, phase transition and drift carrier mobility. Interestingly, the blends exhibit high hole mobility comparable to that of 9TNAT9 and even in the low component ratio of 9TNAT9, the hole mobility is not decreased to the normal level of unaligned P3HT. The ionization potentials of these two compounds indicate the generated hole spontaneously goes to P3HT domains and thus, well-aligned P3HT may be formed by addition of small molecular liquid crystalline semiconductors.

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Asymmetric alkyl BTBT LC semiconductor with a fluorophenyl group, 2-dodecyl-7-(4-fluorophenyl)-[1]benzothieno[3,2-b][1]benzothiophene (FPh-BTBT-C12) was studied on charge carrier mobility by time-of-flight (TOF) method correlated to the mesomorphism. FPh-BTBT-C12 exhibits highly ordered smectic mesophases with the temperature range from 141 °C to 273 °C. TOF measurements of carrier mobility were carried out to show negative charge carrier transport and the observed mobility is in the order of 10^-2 cm² V^-1 s^-1 in the mesophase. The introduction of fluorophenyl group on BTBT core part leads the electron transport.

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In previous study, we reported that vacuum-deposited pentacene thin film on a polymer gate insulator having molecular alignment capability showed well-oriented crystal structure with large orientational dependence of the carrier mobility. In this study, we have used C₈-BTBT as an organic semiconductor material to investigate the molecular alignment properties on UV-processed polymer gate insulators. We make C₈-BTBT thin film by using two methods of spin-coating and vacuum-evaporation, and the structural and electrical properties of C₈-BTBT thin film are studied. We show that vacuum-evaporated C₈-BTBT thin film is well-oriented molecular structure, which results in large orientational dependence of the carrier mobility.

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We have investigated processability of mono-alkylated Phenyl-benzothienobenzothiophene (Ph-BTBT) derivatives having various alkyl chain lengths from C₆ to C₁₄ in fabrication of polycrystalline thin films by solution process and their characteristics of field effect transistor (FET). All Ph-BTBT derivatives show smectic E (SmE) phase and give uniform polycrystalline thin film easily when the SmE films are used as a precursor. The Ph-BTBT derivatives having short alkyl chain lengths show high solubility and good solution processability because they exhibit SmE phase at low temperatures, while Ph-BTBT having long alkyl chain length show relatively low solubility, but give high FET mobility over 15 cm²/Vs after thermal annealing.

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Double-shot inkjet printing of LC semiconductor thin-films was studied by MD simulations. Our results confirmed importance of smectic liquid crystalinity in this printing process.

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We prepared crosslinked azobenzene liquid-crystalline polymers (CLCPs), which contain dynamic covalent crosslinking points based on transesterification between phenyl benzoates and hydroxyl groups in the side chain. Although permanently crosslinked polymers can not be remolded, the CLCP films were remoldable through transesterification reaction when heated at 80 ℃ Upon exposure to UV light, the CLCP films with aligned mesogens by applying external force under heating bent toward a light source, and when irradiated with Vis light, the bent film reversed to the initial state.

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Photonic crystals show the photonic band gap which prohibits propagation of the photon in a certain energy range. Multi-bilayered films are known as one dimensional photonic cystals having optical periodicity with different refractive indices. Multi-bilayered films reflect light of specific wavelength, and the reflection wavelength is related to the film thickness and refractive indices of each materials. In this study, we investigated the structure effect of azobenzene polymer on out-of-plane molecular orientation behavior, and reported switching of molecular orientation in one dimensional photonic crystal.

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We produced meso-scale phase separation composed of nematic liquid crystal and liquid crystal polymer with targeted properties such as domain size and orientation order, although it's difficult to achieve photo-polymerization induced phase separation (photo-PIPS) using reactive mesogen monomer. Then, we realized various thermo-operated optical attenuators, which are able to control optical transmittance by switching between transparent and opaque states. The device is expected to be applied to smart windowpanes, whose solar transmittance into buildings can be controlled as a function of seasons.

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We report the formation of a uniform lying helix (ULH) in a thick cholesteric liquid crystal cell, using an oscillatory shear flow and an electric field across the cell. The helix axis was formed perpendicularly to the shear flow in the cell-plane direction. The cholesteric liquid crystal transitioned from a focal conic texture to the ULH at a critical shear rate. The critical shear rate was in inverse proportion to the cell thickness, and thus our method easily demonstrated a defect-free ULH even in a 54-μm-thick cell.

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Blue phases are liquid crystal phases having cubic lattices with lattice periods of several hundred nanometers. In this study, lattice orientation dependence of electro-optical properties in a polymer stabilized blue phase (PSBP) was investigated for multi-domain samples by a new measuring system combining a microscopic reflection spectrum and microscopic electro-optics. Relationship between the lattice orientations and the electro-optic effect was revealed.

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Liquid crystal is a high-functional material with a large optical anisotropy and fluidity. Molecular reorientation of liquid crystal (LC) can be sufficiently controlled by photophysical processes. Upon irradiation above a threshold light intensity, intermolecular interaction of the excited dye molecules and the LC molecules changes the molecular orientation of the dye-doped LC. Recently, we have reported that oligothiophene-doped polymer-stabilized LC undergoes an alignment change at the lowest light intensity. In this study, we examined the effect of cross-linking in the molecular alignment.

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Control of molecular alignment is important to functionalize soft materials. Two approaches were conducted to induce molecular alignment; mechanical alignment by stretching or rubbing and photoalignment. These processes were widely investigated but have problems such as contamination of dust in rubbing and necessity of high intensity polarized light in photoalignment. We have recently found that anisotropic monomers are aligned through photopolymerization with moving light. In this process, we also found that a periodic structure was formed spontaneously in the obtained polymer film. In this study, we fabricated the polymer films with periodic structures, and observed the film with a polarized optical microscope.

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By using an ultraviolet-curable nematic liquid crystal material, some designed patterns can be stored in the liquid crystal cells with areas polymerized under isotropic and nematic phases. We have proposed a security device that uses the random pattern of optical texture in each cell. In other words, the random patterns of schlieren in each cell can be used as identifiers. For security system using these devices, it is necessary to develop the computer-based system capable of comparing optical texture patterns. In this research, methods of extraction of written patterns were studied for security system.

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Self-assembled materials consisting of organic molecules have attracted a great deal of attention for application in energy devices. In particular, liquid crystals with well-defined channels for the transport of ions are prospective as electrolytes. Recently, we applied layered 2-dimensional liquid-crystalline (LC) ion conductors in lithium batteries and dye-sensitized solar cells (DSSCs). In the present work, LC ion conductors composed of carbonate functionalized rod-shaped mesogens and ionic liquids (ILs) have been developed and applied in DSSCs. The liquid crystals show layered smectic A phases in wide temperature ranges, up to over 110 °C. Remarkably, the DSSCs based on these electrolytes show significant improvement in power conversion efficiency on heating and can continue to operate until over 100 °C. Furthermore, the LC-DSSCs show high open-circuit voltage compared to IL based devices. These results promote liquid crystals as a new class of electrolytes for solar cells capable of efficient conversion of light into electricity at elevated temperatures.

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Nowadays liquid crystal materials have attracted considerable attention for realizing these electrically controllable microwave and milliwave components because they have a large dielectric anisotropy in the microwave and milliwave region. But liquid-crystal-loaded microwave and milliwave devices have one serious problem, that is, the response time when the driving voltage is removed, is very long as the order of 10 s, because the thickness of their liquid crystal layer is typically more than 50 μm. In this study, we discuss about using polymer stabilized nematic liquid crystals for improving the response time.

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The terahertz region of electromagnetic wave spectrum is ranging from 0.1 to 10 THz. There have been various studies for terahertz wave applications such as broadband communications, non-destructive testing and medical imaging. For the next phase of terahertz wave application, high quality of terahertz optical elements will be important. Liquid crystal materials show relatively large refractive index anisotropy in terahertz region of the electromagnetic spectrum and they are strong candidates for functional quality terahertz optical elements. In this study, we discuss the diffraction properties of liquid crystal grating for terahertz wave polarization measurement.

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lossless Dyakonov surface waves (DSWs), which propagate at the interface between two dielectric media with different symmetry, such as isotropic and anisotropic, have great potential in optical and sensing device application. However, it is extremely hard to experimentally observe DSWs because of their stringent existence condition. In this study, we employ metallic nanoparticle-dispersed liquid crystal (NDLC) as a supporting medium of DSWs and investigate the existence condition of DSWs in such NDLCs. We have shown that a small amount of Ag nanoparticle inclusion significantly relaxes the existence condition of DSWs. Orientation of liquid crystal molecules can be controlled by external stimuli, therefore our findings might open the door for the development of novel type of optical devices based on lossless DSWs.

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We propose a liquid-crystal (LC) lens with highly-resistive and circularly-patterned transparent films. The highly resistive films with two different diameters and sheet resistivities are fabricated by using a radio frequency (RF) sputtering process. The interference fringes of the LC lens can be observed by a polarizing microscope under cross polarizers and then the optical phase profile of the convex lens property can be derived by measuring the interference fringes. The parabolic distribution of the phase profile and large lens power properties can be attained by applying relatively high voltages to two electrodes of the LC lens.

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We calculate liquid crystal (LC) director distributions and optical phase profiles in an LC micro-lens-array (LC-MLA) with two-divided and tetragonally-patterned electrodes by using a numerical calculation method. The prism and lens-like phase difference distributions in the rectangular aperture region of the LC-MLA with the periodic structure are discussed. The LC molecular orientations in the rectangular region can be estimated and its phase profile can be predicted well by the molecular orientation calculations.

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A new type of tunable Fresnel liquid crystal lens was developed with only plane glass plate. We first discuss with electro-magnetic simulations and achieved a saw-tooth distribution of electrical potential in the liquid crystal material by using concentric interdigitated array electrode, high-resistivity thin film layer and also originated insulator gaps below the boundary of the electrodes. We then fabricate the liquid crystal lens employing the proposed design and characterize its performance under an optical microscope. Our design enables the attainable lens power to be expanded by approximately 10 times, leading to the realization of versatile lens systems without any moving components.

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We studied the molecular dynamics of chiral and achiral smectic liquid crystals by solid-state ¹³C nuclear magnetic resonance (¹³C-NMR) spectroscopy with a Larmor frequency of 100 MHz. The chiral and achiral smectic liquid crystals used were S-4-(1-methylhexyloxycarbonyl)phenyl 4'-octyloxybiphenyl-4-carboxylate and 4-(hexyloxycarbonyl)phenyl 4'-octyloxybiphenyl-4-carboxylate, respectively. The peak width and the spin-lattice relaxation time were measured to investigate the effect of chirality on the molecular dynamics. The ¹³C-NMR study revealed that introducing chirality, namely, the introduction of a (-CH₃) group to the C23 carbon, affects the intramolecular correlation between the mobility of the carbon and the rotational motion of the aromatic core.

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Optical properties of the binary mixtures of ferroelectric MC881 and antiferroelectric MC452 were measured to investigate the phase transition between ferroelectric liquid crystal (FLC) and antiferroelectric liquid crystals (AFLC). An improved method measuring electric-field-induced birefringence (EFIB), optical rotational power (ORP) and selective reflection at the same time was put forwarded here for the first time. Using this equipment, we confirm that the most easily deformable region in the E-T contour diagram arises from the divergence of helical pitch rather than the emergence of the subphase. This easily deformable behavior can be used in novel display technology in the future.

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A dynamic viscoelastic measurement can be used for a study on the phase transition behavior of liquid crystals, because this measurement is sensitive to the structural change accompanied by the phase transition. In our previous study on the dynamic viscoelastic properties of cholesteryl derivatives, the unusual behavior of the storage modulus was observed in the cholesteric phase, whereas no phase change was observed around that temperature region. In order to discuss the relationship between the unusual behavior of the storage modulus in the cholesteric phase and the molecular structure, cholesteric liquid crystals without cholesteryl group have been synthesized and their dynamic viscoelastic measurements have been made in this study.

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A photochemical behavior of a dendrimer having peripheral cinnamate mesogens containing azo group was examined by measurements of UV-vis spectra both in solution and in film. D2-6AC2 in solution showed two absorption maxima at 289 and 370 nm. Upon UV irradiation, the absorption at 370 nm decreased and those at 289 and 470nm increased due to the isomerization of azobenzene from E- to Z-form. Almost 27% of the Z-form of D2-6AC2 was isomerized to E-form upon visible light irradiation, whereas 78% of D2-6Azo6, which has azobenzene mesogen without cinnamate group, could be isomerized. Thus the cinnamate moieties in D2-6AC2 dimerized during the UV irradiation to prevent the isomerization from Z-to E-form.

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