The chirality of helical director orientation of the cholesteric gels, which are the cholesteric elastomers(ChE) swollen by chiral liquid crystal solvents, is investigated for the two types of ChE which are prepared by chiral imprinting method, i.e., the cross-linking of achiral mesogens in the presence of a nonreactive chiral dopant, and by cross-linking of chiral mesogens. Two types of chiral liquid crystal solvents with different chiralities are employed as the swelling solvents.

View full abstract

Cholesteric liquid crystalline (CLC) core-shell microcapsules (MCs) function as various optical devices, such as omnidirectional laser resonator. For optical phase control of the laser action, we focus on the control of the orientation of CLC-MCs. We have successfully controlled the orientation of a CLC-MC with a needle-like aggregate in one disclination line in the CLC shell. Here, we report that CLC-MCs with a low viscosity of outer phase are reoriented faster than that with a high viscosity. This result indicates that the needle-like aggregate doesn't migrate in the steady CLC phase, and instead, the whole CLC-MC is reoriented in a uniform magnetic field.

View full abstract

A recent study has indicated that the alkyl chain of nTCB is fully disorderd even in the smectic E (SmE) phase and the rigid core and alkyl chain microscopically segregate each other. However, molecular dynamics in the SmE phase has been unknown so far, in contrast to other liquid crystalline phases such as nematic (N) and smectic A (SmA) phases. We investigate the molecular diffusion of a fluorescent molecule in SmE phase by employing the fluorescence recovery after photobreaching (FRAP), and compare the results with those in N and SmA phases.

View full abstract

The binary systems of mono-disperse hard-rod-like particles with different diameters have been predicted to segregate into smectic phases by the numerical experiments and computer simulations. This segregation is entropically driven based on the steric repulsion between particles. In this study, we present an experimental finding of the predicted segregation by atomic force microscopy (AFM) observations and synchrotron radiation small- and wide- angle X-ray scattering measurements (SR-SAXS and SR-WAXS) in the thermotropic LC systems of the binary mixtures of the polysilanes with different alkyl side chain length, Poly{n-tridecyl-(S)-2-methylbutylsilane}, Poly{n-dodecyl-(S)-2-methylbutylsilane}, Poly{n-undecyl-(S)-2-methylbutylsilane} and Poly{n-decyl-(S)-2-methylbutylsilane}, which can be regarded as rods with different diameters.

View full abstract

Compound 1 possessing two urea groups in the molcule were designed and synthesized. Its phase transition was measured by polarized light optical microscopy and differential scanning calorimetery. In Xray diffraction measurement, it was classified that compound 1 exhibited a rectangular columnar phase. To confirm its ferroelectricity, optoelectronic and SHG experiments were carried out.

View full abstract

Achiral bend-shaped molecules are known to show chiral liquid crystal phases, which have attracted attention as a new formation mechanism of the chiral molecular aggregates without molecular chirality. Furthermore, de Gennes et al. theoretically predicted that dumbbell-shaped molecules having bulky substituent at their both ends could easily induce helical structure due to an asymmetric interaction in molecular packing. In this study, a novel achiral dumbbell-shaped molecule was synthesized and the effect of enhancing chirality of liquid crystal by adding the molecule to a chiral nematic phase was investigated. By the addition of the dumbbell-shaped molecule to a chiral nematic phase, the helical pitch of the chiral nematic liquid crystal is decreased. This result indicates that the molecule prevents inducing chirality in liquid crystals.

View full abstract

We designed an asymmetric dimer possessing a terminal hydroxyl group, and investigated the phase transition behavior using polarized optical microscopy and differential scanning calorimetry. The dimer exhibited a nematic phase. On cooling from the nematic phase, two domains with different textures were formed in the crystal. On heating from the crystal, nematic and crystalline phases were found to coexist in a temperature range of 18.2 K. We discuss how intermolecular interactions cause such an unusual phase separation.

View full abstract

A series of polymethylenes with phenyl benzoate mesogen groups linked to each backbone carbon atom via an alkyloxycarbonyl spacer was prepared and their liquid crystal structures were investigated by wide-angle X-ray diffraction method. The liquid crystalline phase behavior of the polymethylenes was largely dependent on the number of spacer carbon atoms. It may be attributed to degree of decoupling of helical main-chain and side-chain mesogen motions. A short spacer can couple helical main-chain and side-chain mesogen motions to let the backbone lose the orientational order due to the isotropization of the side-chain mesogens. On the other hands, the long spacer decouples them to make the polymethylene form a hexagonal columnar phase though the side-chains are in the isotropic state.

View full abstract

We have synthesized oriented liquid crystal slide-ring polymer (LC-SRP), which composed of LC monomer, blocked isocyanate monomer and polyrotaxane derivatives having vinyl groups, by uniaxially stretching method. The thermal stability of obtained orientation was improved with formation of crosslinks by the reaction of the isocyanate groups regenerated in the LC-SRP network.

View full abstract

The formation of micelles generally changes according to the form of surfactant molecules and their concentration, and there is the cis-trans transition in the azo-molecules under the UV light. In this paper, we found that the azo-doped nematic phase of rod-like micelles under the UV light turned into isotropic phase in the second order. We measured the relaxation time of azo-doped lyotropic liquid crystals under the UV light by using dynamic light scattering (DLS) and found that the transformation of rod-like micelles including azo-molecules might induce the N-I transition.

View full abstract

Liquid-crystalline (LC) semiconductors are able to form thin films by solution processes. In-situ polymerization of LC semiconductor is effective to produce macroscopically aligned semiconductor films. In this study, we synthesized a perylene tetracarboxylic bisimide (PTCBI) derivative bearing heptamethylcyclotetrasiloxane moieties at terminal positions of the alkyl chains, and produced thin films with a spin-coating method. We studied physical properties of the as-deposited and polymerized thin films.

View full abstract

We have already reported that n-type liquid-crystalline (LC) semiconductors, perylene tetracarboxilic bisimide (PTCBI) derivatives bearing cyclotetrasiloxane moieties. This compound shows columnar phases at room temperature due to nanosegregation between flexible cyclotetrasiloxane rings and rigid π-conjugated cores. In the columnar phases, the efficient electron transport has been observed. Furthermore, the ring-opening polymerization can stabilize and insolubilize the LC thin films deposited by a spin-coating method. In this study, we synthesized and characterized LC PTCBI derivatives bearing cyclotetrasiloxane rings and an ionic moiety. Hybridized functions are possible in the LC phases having nanostructures by combining ionic and electronic conductions.

View full abstract

Miscibility is a characteristic property of liquid crystals (LCs) and has been utilized in LCD technology to control some of physical properties such as temperature range and viscosity. However, miscibility of LCs has not yet been studied as a tool for developing new organic semiconductor systems. We studied that binary mixtures of the dithienylnaphthalene homologues, 2,6-di(5'-alkyl-2'-thienyl)naphthalene (nTNATn:n=carbon number in an alkyl chain) in terms of miscibility and charge transport properties. The octyl homologue (8TNAT8) was already reported to show a high hole mobility in both highly ordered mesophase and crystalline phase in the order of 10^-1 cm²V^-1s^-1. It was found that the binary mixtures of these homologues tend to show miscibility in the highly ordered mesophase and the carrier mobility depends on the component ratio except for the mixture with the non-mesogenic homologue which exhibits the higher mobility than those of others.

View full abstract

Since the power generation efficiency of organic photovoltanic (OPV) cells is lower than that of conventional Si solar cells, OPV cells has not been put into practical use. In order to improve the efficiency, we try to increase the interface area between a p-type layer of pentacene and an n-type layer of C_<60> by using UV patterning method. The method is applied to obtain the selective deposition of pentacene film on UV-patterned SAM film. As a result, interface roughness between pentacene and C_<60> is controlled, resulting in improving the efficiency of OPV cells.

View full abstract

Blue phase is an attractive liquid crystal because of the 3-dimensional nano-structure. In the previous study, we have examined the mechanical strength of the solidified blue phase. As a result, we found that the solidified blue phase samples were more fragile than the solidified samples which have been photocured in the choresteric phase. This fact may result from a discontinuous latiice including defect, i.e. platelet texture, as seen in microscopic texture observation. In the present study, we investigated obtaining a uniform orientation of the blue phase by applying an orientation treatment.

View full abstract

Ferroelectric liquid crystals (FLCs) are attractive for a next generation of LC display having high performances such as high-quality display for a moving video image and very low power consumption, because of their unique characteristics such as high-speed response. However, it is difficult to obtain the uniform alignment because the structure is easily affected by the surface topography. Therefore, we focus on vertical alignment FLCs (VAFLCs). High contrast ratio is expected because the fabrication of VAFLC cell does not need the rubbing.In this study, we have examined the optimum conditions for the fabrication of uniformly VAFLC cell.

View full abstract

A laser is an attractive light source because of its high efficiency and brightness with low power consumption and long lifetime, pure color and extremely wide color expression that can be realized by choosing the wavelength of laser light, and high directivity and small etendue of light which contribute to downsizing. These characteristics are strong merits, especially for a projection display system. However, there is a serious problem in utilizing a laser as a light source. Strong interference occurs, originating in the high coherency of laser light and the surface topography of objects such the screen. This is well known as "speckle noise". Therefore, the suppression of speckle noise is necessary for laser displays such as these in an image projection system. In this study, in order to reduce the speckle noise, we used liquid crystal devices that have electrically controllable optical characteristics.

View full abstract

Ferroelectric liquid crystals (FLCs) are attractive for a next generation of LC display (LCD) having high performance such as high-quality moving video image and very low power consumption, because of their unique characteristics such as high-speed response, wide viewing angle and bistability. However, the bistability is disadvantageous for LCDs which possess grayscale or full-color capability. Therefore, we introduce polymerstabilized FLCs (PS-FLCs), in which a photocurable mesogenic monomer is doped into an FLC and UV photocuring is carried out in the SmA phase at the quiescent condition, may show monostable and V-shaped electrooptical characteristics with a grayscale capability without a threshold.

View full abstract

Landau expansion of free energy assuming dual instabilities for nano-segregated SmA phase is analyzed as a function of the difference in temperatures where each instability takes place. It is shown that the discontinuous phase transition driven by the nematic order disappears at a critical point if the segregation instability occurs at a sufficiently higher temperature than the instability for the nematic order.

View full abstract

In nematic liquid crystals, flow influences molecular orientation, and vice versa. Although the coupling has been widely demonstrated for macroscopic flows, there may be no experimental evidence for microscopic flows at equilibrium. Under these circumstances, we have performed a simultaneous observation of a Brownian particle trapped with optical tweezers and the director field to verify it in the level of fluctuations. The cross-time correlation function between the spatial gradient of the director field and the particle displacement manifests the existence of the coupling between the flow and orientation.

View full abstract

We examined the anchoring force of nematic liquid crystal (NLC) on high-density polystyrene (PS), poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA), and poly(hexyl methacrylate) (PHMA) brushes for by the electro-optical properties of the in-plane switching cells consisting of polymer-grafted substrates. With increasing temperature the anchoring coefficient began to decrease at a temperature which correlates with the glass transition temperature (T_g) of each polymer.

View full abstract

For improved optical properties of liquid crystal displays, it is important to determine the cell thickness and the wavelength dispersion in birefringence of liquid crystals. In conventional ways, it was not possible to determine the wavelength dispersion unless the cell thickness or a birefringence Δn is known. In this study, we investigate the way to determine cell thickness d and wavelength dispersion of ne and no with the values of no at wavelength of 589nm.

View full abstract

Some negative type liquid crystals (LCs) align perpendicular and neutral type LCs align parallel to the rubbing direction on a polyvinyl imidazole (PVIz). In this study, we mixed LCs which aligns perpendicular and parallel to the rubbing direction and investigated the alignment direction of LCs mixtures. A separation of the alignment which might be caused by a selective adsorption of the LC on the PVIz surface was observed when the LC mixture using negative types of LC with CN groups was injected in the isotropic phase.

View full abstract

It has been known that an electrospinning method is one of spinning methods for filaments with a micron order of diameter. If a configuration of micro-filament within the LC cell is applied to the alignment control of LC director, it will have possibilities to realize some novel LCD methods of LC orientation. The filament was spun using mixture materials hydroxypropyl cellulose and the UV curable LC monomer, UCL-008 (DIC). The filaments was set within the LC cell after irradiating the UV light. In some parts around filaments, it was observed that the LC director was tilted from parallel to the filament.

View full abstract

Microbeam resonant X-ray scattering experiments recently revealed field-induced superlattice structures that have unexpectedly large unit cells consisting of 12- and 15-layers [1]. We have tried to explain their emergence by the long-range interlayer interactions (LRILIs) based on the Emelyanenko-Osipov quasi-molecular model [2] together with our primitive way of understanding the frustration in clinicity [3].

View full abstract

Chiral paramagnetic nitroxide radical (NR) liquid crystalline (LC) compounds have a great potential as novel molecular materials because they would be expected to show some fascinating features such as magneto-optical effects. However, their high LC phase temperature range resulting from high melting point interferes with both basic and application researches as the novel materials. Therefore, low-temperature chiral NR-LC compounds are eagerly anticipated to be synthesized. Here, we report the first design and synthesis of low-temperature NR-LC compounds containing a fluorine atom in a molecular core, which affects molecular planarity and symmetry.

View full abstract

We have reported the first ferroelectric columnar liquid crystal with a spontaneous polarization along its columnar axis. However, the rate of polarization reversal is very slow and it is not practically useful. Hence, we are tackling this challenge especially by modifying molecular design of side chains. In this poster presentation, we will report the molecules newly developed toward the above goal and their physical properties.

View full abstract

Molecular orientation induced by photoalignment method has attracted much attention in display applications. We have found that molecular alignment is induced at the boundary between the exposed area and the non-exposed area in masked photopolymerization process. However, detailed mechanism remains unclear. In this study, we produced films by masked photopolymerization and evaluated the molecular alignment behavior and surface structure by polarized optical microscopy and atomic force microscopy.

View full abstract

Recently, the cause of the light leakage from pixel edges with high resolution LC panel has been noticed. In general, the flexoelectric effect is suspected as one of causes. Then, the evaluation of flexoelectric effects is important. However, that evaluation is not easy because flexo effects dominantly appear under the dc electric field, i.e., the problem is a separation from impurity ions. We have attempted to measure the flexo-coefficients with the pure LC materials by using the chromatographic effects during the LC injecting process. Now, approx. 50pC/m of the coefficient (e_<11>+e_<33>) with ZLI-4792 was obtained, however, it is under consideration for measurement conditions.

View full abstract

Gold(I) complexes have received considerable attention as promising light-emitting materials because they strongly luminesced in condensed phases due to an aurophilic interaction, which depends on the distance between two gold atoms. It means that the luminescent behavior of gold complexes can be changed by controlling their aggregated structures. Recently, we have focused on the gold complexes with liquid-crystallinity (LC) to control their aggregated structure and successfully discovered various sorts of LC gold complexes. In this work, we discovered intriguing LC gold complexes that can spontaneously form nano-sheet structure of Au atoms in the crystalline phase. We discuss their luminescent property and electrical conductivity, and the correlation between their intriguing aggregated arrangement and properties is discussed in detail.

View full abstract

We have prepared uniaxially oriented main-chain liquid-crystalline elastomers composed of BB-n smectic polyesters with trifunctional cross-linkers and reported the deformation behaviour in a cyclic heating-cooling process, where successive phase transformations occur. Although the elastomer contracted by about 650 % on heating from room temperature to the isotropic phase, the sample length recovered by 450 % on cooling to room temperature in the first heating-cooling process. We have observed that the elastomer once exposed to the isotropic phase exhibited reversible shrinkage and elongation, estimated at about 450 %, during the transformation between the isotropic and liquid-crystalline phases. In addition, X-ray analysis has revealed that the cybotactic nematic state emerges in the oriented main-chain liquid-crystalline composed of the smectic polyesters. Moreover, we have confirmed that the magnitude of deformation of the elastomers is non-linearly coupled with the orientational order parameter estimated by X-ray scattering observation.

View full abstract

We have studied self-assembling behavior of two-component systems based on monoureapyridines or cyanobiphenyl-containing aliphatic amines. Gelation properties in common organic solvents and mesomorphic behavior in bulk states of these compounds or complexes were examined. Among the single component of monoureapyridines, 4-aminopyridine derivatives efficiently gelate hydrocarbons and tetrachloromethane. The addition of silvertrifluoromethane sulfonate (AgOTf) to the 4-aminopyridine-derived monoureapyridines changed self-assembling behavior. The addition of AgOTf to monoureapyridines derived from 4-picolylamine induces efficient gelation abilities, while the single component of these compounds exhibits no gelation abilities. On the other hand, mesomorphic behavior is observed for the silver complexes based on the 4-aminopyridine-derived monoureapyridines.

View full abstract

π-Conjugated liquid crystals have great potential to be applied in organic optoelectronic devices. In this study, we designed X-shaped oligothiophene-pyrene conjugates with twelve or eight alkoxy chains at their extremities. They exhibited hexagonal and rectangular columnar phases. The time-of-flight photoconductivity measurements revealed that these compounds showed the hole mobilities in the order of 10^<-4> cm^2 V^<-1> s^<-1>. In addition, the X-shaped molecule with twelve or eight alkoxy chains showed mechano-responsive photoluminescent behavior.

View full abstract

To realize high density memory devices, a supramolecular compound was designed and synthesized. This compound is composed of a central urea and two trialkoxy benzoic acids possessing six polymerizable sites. After polymerization, it was expected that the polymer network stabilized the polarity of the linear urea network. To investigate the liquid-cristallinity and electro-responsiveness, polarlized optical microscope (POM), X-ray diffraction (XRD), and triangular wave voltage application are used.

View full abstract

Mesomorphic urea compound 1 and polymerizable compound 2 were synthesized. Compound 1 exhibited a columnar mesophase. Though compound 1 showed a ferroelectric behavior, the polarity did not maintain because of the electrostatic repulsion between columns. Intercolumnar polymer network was structured in the columnar phase of 1 by addition of 2 followed by its polymerization. This network increases threshold between two polarized states. Realization of ferroelectricity is expected by that.

View full abstract

The effect of competing interactions such as hydrogen bonding, π-stacking and dipole-dipole interactions on the discotic liquid crystalline phases has been examined. Two series of isomeric tetraalkoxydibenzophenazine amides with different alkyl chain length were prepared; a tertiary diethyl amide with no H-bond donating ability and a secondary butyl amide with both H-bond donating and accepting ability. Both types form hexagonal columnar phases in wide temperature ranges, while butyl amide possesses higher clearing temperatures than diethyl amide. A comparison of the phase behavior with other dibenzophenazine derivatives indicates that the columnar phase of the butyl amide is stabilized by hydrogen bonding, likely at the expense of local antiparallel alignment of these molecules.

View full abstract

Amphiphilic random copolymers with hydrophilic oligo(ethylene oxide) and hydrophobic azobenzene side chains (PAzA-r-PMEOMA) are synthesized. A PAzA-r-PMEOMA thin film was prepared by spincast method. Surface wettability change of the thin film with UV irradiation was measured by air bubble contact angle. UV absorption spectroscopy revealed that the photo induced wettability change in water is involved by the H-aggregation of azobenzene side chain. The surface wettability with non-aggregating azobenzene chromophore was almost unchanged with UV irradiation in water. These results indicate that the aggregation of azobenzene side chain play an important role in the photo induced surface wettability change.

View full abstract

Redox-active liquid crystals that have both liquid crystalline and redox properties are expected to give new and attractive electronic devises controlled by electrochemical methods at ambient conditions. We have reported the design and properties of Pt(II) metallomegens possessing redox-active catecholato or benzenedithiolato and long alkyl chain-substituted bipyridine ligands. Especially, metallomesogen possessing 3,5-t-butylcatecholato shows direct electrochemical redox responses and electrochemically -induced transformation between columnar liquid crystal and isotropic ionic liquid phases. In this work, the effects of coordinating atoms, the position of substituents, temperature, and electrolytes on electrochemical property of metallomesogens will be presented.

View full abstract

Liquid crystal compound (8BP(Cl)MB) which exhibits flexoelectric effects in the cholesteric phase was synthesized. In this study, novel compounds (8BP(Cl)MB, R8BP(Cl)MB) have been synthesized. Phase transition temperatures and the textures under polarization microscope were measured. The relationship between the moleculer structure on the electric field induced phase transitions are discussed.

View full abstract

The electric field response of cholesteric liquid crystal mixture was investigated. It has been shown that a cholesteric LC 8BP(Cl)MB exhibits a flexoelectric effect. In this study, 8BP(Cl)MB with a branched chain was synthesized and mixed with 8BP(Cl)MB, were examined and the effect of the addition of LC with branched chain was investigated.

View full abstract

The radical polymerization of the 0th generation liquid crystalline polypropyleneimine dendron (4) was carried out to give polymethacrylate 5. DSC thermograms indicated that the dendron 4 and the resulting linear polymer 5 were thermotropic liquid crystals. Polarizing optical microgram (POM) image of 5 showed a typical focalconic fan texture due to smectic phase. When the mixture of their a linear polymer 5 and nematic liquid crystal (1/99, wt/wt) was heated to isotropic melt and then gradually cooled, the dark field was observed. Conoscopic observation showed a typical isogyre and indicates the homeotropic orientation on the glass. Thus small amount of 5 could induce NLC to align vertically.

View full abstract

We found a triphenylene mesogen having six azobenzene moieties with ester linkage exhibits both calamitic and discotic mesophses as photo-induced isothermal as well as thermal phase transitions. In order to discuss on the effect of linkage groups on the bimesomorphism, two types of ether-linkage derivatives were prepared to clarify the thermal and photoinduced phase transitions. It was found that only one rod-like smectic A phase is observed in one derivative, while the other show some LC phases. The phase transition temperatures are decreased by ca. 7.5 or 16.5 ℃ in comparison to the ester linkage one. This is due to the increase of the flexibility at the linkage parts. The isothermal phase transition of ether derivatives between liquid crystal and Isotropic phases were observed by controlling the intensity of UV light.

View full abstract

Viologen compounds having different counter anions (12V12X, (X = Br, BF₄, Tf₂N)) were synthesized. Photoresponsive behavior of 12V12X in chloroform or DMF was investigated under atmosphere by measurement of UV-vis absorption spectra. All of the viologen compounds formed a dimer in solvents, when they irradiated with UV light. The dimer was considered to be formed through radical cations produced by the UV irradiation. 12V12Tf₂N formed liquid-crystalline phases. Therefore, 12V12Tf₂N sandwiched between two slices of quartz glass were reduced at 190 ℃ upon irradiation with UV light.

View full abstract

A supramolecular liquid crystal is a self-assembling chemical system of which component molecules are bonded by non-covalent bonds such as a hydrogen bond, as a result, it exhibits a liquid crystallinity. It is well known that nucleic acid bases form hydrogen-bonded assemblies and each nucleobase specifically forms a Watson-Crick base pair with its complementary partner in DNA double helix structure. We focused on the supramolecular complex containing nucleic acid bases which is expected to exhibit a liquid crystallinity. In this study, a series of adenine and thymine derivatives were synthesized and the phase transition behavior of their complexes was investigated.

View full abstract

A hydroxypropyl cellulose (HPC) is one of cellulose derivatives and it is used in various fields, food, medicine and so on. The HPC aqueous solution has a lyotropic liquid crystal phase and is colored by a selective reflection. The wavelength of the selective reflection is depending on a kind of additive ions and its concentrations. And the wavelength can be changed by applied voltage which changes the concentration of additive ions by electrophoresis. In this study, HPC liquid crystal with various ions was fabricated and its properties were measured.

View full abstract

The polarized switching by flexoelectric effects was attempted using a HAN cell with bistable surface. The groove structure for the bistable surface was duplicated from a prism sheet with 1μm pitch to the UV curable resin film on the substrate surface. The rubbing treatment was done normal to the groove direction. The nematic mixture ZLI-4792 was injected into the cell, and the switching between two states was attempted under the dc electric field with interdigit electrodes. Under existing conditions, the bistable switching was observed, however, the memory function was not obtained. It seemed that the sufficient condition for memory function might be not obtained.

View full abstract

We synthesized nonpolar liquid crystalline molecules consisting of hydrogen and carbon atoms. The rod-like compounds exhibited nematic liquid crystal phases. Despite the lack of hetero-atoms or polar groups, our nematic compounds showed electro-responsiveness in their retardation. We investigated their phase transition behaviors and liquid crystallinities by using a polarized light microscope (POM), a differential scanning calorimeter (DSC), and one- and two-dimensional X-ray diffractometers (1D-XRD and 2D-XRD).

View full abstract

There is a strong demand for realizing intermediate LC pretilt angle for newly developed LCD mode such as OCB or bistable LCD. In the present study, we propose a new method to control the LC pretilt angle based on surface modification of polyimide alignment layer by atmospheric-pressure plasma treatment. We found that atmospheric-pressure plasma treatment can adjust the wettability of polyimide surface with long alkyl side chains and so that the pretilt angle can be controlled from vertical to arbitrary degree.

View full abstract

Previously, it was shown that the response time of LCD can be improved by doping nanoparticles into host LC. However, It is not clarified which physical parameters such as elastic constant, dielectric constant and anchoring energy have an influence on the LCD performance. In this study, nematic LCs with and without nanoparticles were prepared and the performance was evaluated by ellipsometry. Polar anchoring energy was measured by SOITE method using ECB-cell without doping chiral dopant. Azimuthal anchoring energy was measured by torque balance method using TN-cell with chiral dopant.

View full abstract