A highly refractive sulfur-containing photosensitive polyimide (PSPI) based on the PI from 4,4'-[p-thiobis(phenylenesulfanyl)]diphthalic anhydride (3SDEA) and 4,4'-thiodianiline (SDA), 4,4'-methylenebis[2,6-bis(methoxymethyl)phenol] (MBMP) as a cross-linker, and (5-propylsulfonyloxyimino-5H-thiophen-2-ylidene)-(2-methylphenyl)acetonitrile (PTMA) as a photoacid generator has been developed. The matrix polymer showed high transparency in the g-line region and the high reflective index of 1.7452 and low birefringence of 0.0081. The PSPI consisting of the PI (84.8 wt%), MBHP (11.0 wt%), and PTMA (4.2 wt%) exhibited the high sensitivity (D_0.5) of 36 mJ/cm² and good contrast (γ_0.5) of 5.1, respectively, producing a clear negative-tone line-and-space pattern with 8-μm resolution.

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A positive-type photosensitive poly(benzoxazole) (PSPBO) based on poly(o-hydroxy amide) (PHA), (5-propylsulfonyloxyimino-5H-thiophene-2-ylidene)-(2-methylphenyl)acetonitrile (PTMA) as a photo acid generator (PAG), and 9,9-bis[4-(tert-butoxycarbonylmethyloxy)phenyl]fluorene (TBMPF) as a dissolution inhibitor (DI) has been developed. The TBMPF was synthesized from 9,9-bis(4-hydroxyphenyl)fluorene with tert-butyl bromoacetate. The PSPBO consisting of PHA (74 wt%), TBMPF (22 wt%), and PTMA (4 wt%) showed the high sensitivity of 28 mJ/cm² and high contrast of 2.7 when it was exposed to a 365 nm line (i-line), postbaked at 100 °C for 2 min, and developed with aqueous alkaline developer, 2.38 wt% tetramethylammonium hydroxide solution (TMAHaq) / 5 wt% iso-propanol (iPrOH) at 25 °C. A clear positive image of 3 μm line and space pattern was printed on a film exposed to 50 mJ/cm² of i-line by a contact printing method and converted into the poly(benzoxazole) pattern upon heating at 350 °C for 30 min. This PSPBO showed good thermal and mechanical properties. The value of dielectric constant estimated from the refractive index was 2.82.

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Hyperbranched poly (ether sulfone)s with imidazolium salts at the termini (HBPES-Im) was synthesized by polycondensation of AB2 type monomers and terminal modification using cation exchange reaction. Then, poly (ether ether ether sulfone)s with imidazolium salts at the side chains (PEEES-Im) was prepared to make the composite membranes. HBPES-Im and PEEES-Im were designed each three kind polymers with different terminal structures. The temperatures at which 5% weight losses (T_d5) of HBPES-Im and PEEES-Im occurred were higher than those of each precursors. HBPES-Im(H,H) and PEEES-Im(H,H) without alkyl chains were also high glass transition temperature (T_g). Blend membranes with HBPES-Im and PEEES-Im were prepared by solution casting method and measured ion conductivities by two-probe conductivity measurement. The blend membrane composed of HBPES-Im(H,H) and PEEES-Im(H,H) showed higher ion conductivity of 2.19X10^-3 S/cm under 80 °C and 90% of relative humidity.

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A new series of organo-silica/polyimide (PI) nano-hybrid materials were prepared by thermal imidization of blended precursors derived from poly (amic acid) (PAA) and polysiloxazane copolymers (DEN). 4,4'-(Hexafluoroisopropylidene) diphthalic dianhydride (6FDA) and 4,4'-diaminodiphenyl ether (ODA) were used to synthesize the PAA of a fully aromatic fluorinated PI (6FDA-ODA), and 1,2:3,4-cyclobutanetetracarboxylic dianhydride (CBDA) and ODA were chosen to prepare the PAA of semi-aromatic PI (CBDA-ODA). Compared with the traditional silica/PI hybrids prepared from sol-gel method, the novel organo-silica/PI nano-hybrids significantly improved the compatibility between PI and DEN components. The FT-IR spectra of the nano-hybrid films showed that Si?O?Si stretching peaks increased as the increase of DEN content. DEN/6FDA-ODA films exhibited higher transparency than the pristine PI, whereas DEN/CBDA-ODA films were slightly opaque due to the poor compatibility between the phenyl rings of DEN and the alicyclic CBDA structure. All the phenomena caused by the organo-silica nano- hybridization, including the slight decrease in refractive indices, the significant decrease in birefringence, and the variations in thermal diffusivity are explainable by the increase of Si?O?Si linkages which form three-dimensional cross-link networks. The DEN/PI nano-hybrids with high silica contents are promising for electronic and optical applications.

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Coronary Stent is recently often used for the revascularization of occluded coronary artery, but bare metal stent often caused restenosis by thrombosis attached on stent. To decrease thrombosis on bare metal stent, the newly developed biomimetics Diamond-Like carbon (DLC) thin film is evaluated after providing high cytocompatibility on the surface of stent by plasma treatment. To investigate the affect of the bonded network into the DLC thin film on plasma treatment, two kinds of DLC thin film were deposited in CH4 and C₂H₂ gases by PECVD. As a result, the amount of sp² C-H and sp³ C-H bonded networks in DLC thin films deposited with C₂H₂ gas (C₂H₂-DLC) decreased and those of sp² C-C and sp³ C-C bonded networks increased compared with those in the DLC thin films deposited with CH₄ gas (CH₄-DLC). NH₃ and O₂ plasma surface treatments were performed for two kinds of DLC thin film. As a result, many functional groups were introduced into the C₂H₂-DLC thin films surface compared with into the CH₄-DLC thin films surface. From these results, the surface of the DLC thin films deposited with C₂H₂ gas were treated with plasma, and their effects on endothelial and smooth muscle cells were studied. It was observed that the endothelial cell growth ratio in the case of the DLC thin films whose surface was treated with plasmas was higher than that in the case of the untreated DLC thin films. Therefore, this test results indicate the newly developed biomimetic DLC thin films coating will be one of the best coating for metalic medical devices.

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The effect of plasma pretreatment on immobilization of heparin on polymer surface was investigated using argon and/or ammonia surface-wave plasmas. Heparin was immobilized by binding with the amino groups introduced by the ammonia plasma on the polymer surface and was confirmed by toluidine blue test and X-ray photoelectron spectroscopy (XPS). The ratio of sulfur contained in heparin significantly increased with the contents of amino groups after the heparin immobilization process. It suggests that most heparins are covalently bound to the amino groups introduced on the polyurethane surfaces.

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Magnesium alloy sheets were coated with diamond-like carbon (DLC) using low-temperature plasma for the improvement of formability. For the better adhesion between Mg and DLC, Si-containing intermediate layer was necessary. In SEM observation, Si-containing layer formed by tetraethoxysilane (TEOS) plasma exhibited very tight and regular waving pattern, which was inherited to DLC layer deposited successively, and showed good adhesion. From the X-ray photoelectron spectroscopy (XPS) measurement, Si-C bond was found at the interface after DLC coating. Concerning the surface chemical structure, both sp³ fraction and hydrogen content measured by XPS and glow discharge spectroscopy, respectively, decreased with increasing CH₄ concentration in the mixed gas with H₂ in DLC coating. The friction coefficient was reduced by the TEOS and DLC coating to a compatible level with MoS₂ lubricated one, but its clear dependence on CH₄ concentration was not found. The formability by deep drawing of DLC coated Mg alloy sheet was as good as that of MoS₂ lubricated one.

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Poly(tetrafluoroethylene) (PTFE) plates grafted with N-isopropylacrylamide (NIPAAm) as a hydrophilic monomer have been prepared by the combined use of the plasma treatment and photografting. The surface compositions of the grafted PTFE plates were analyzed by ESCA and the thermo-responsive properties followed by contact angle measurements. To obtain a high grafted amount of PNIPAAm, we cured oxygen-plasma-treated PTFE plates in oxygen atmosphere or after being dipped in acetone and methanol. Alternatively, we prepared the PTFE plates through the method of discontinuous and continuous irradiation of oxygen-plasma treatment. Then, the plasma treated PTFE plates were photografted in an aqueous 1.5 mol/dm3 NIPAAm solution. The ESCA spectra revealed introduction of groups containing oxygen and NIPAAm onto PTFE plates. The grafted amount of PNIPAAm onto PTFE increased over continuous oxygen plasma irradiation. Further, the grafted amount of PNIPAAm was proportionally effective to the thermosensitivities of the PTFE-g-PNIPAAm plate.

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Highly transparent conductive polycrystalline Ga-doped ZnO (GZO) films with a thickness of about 100nm prepared on cyclo-olefin polymer (COP) or glass substrates at various temperatures below 90(C by ion plating with DC-arc discharge were investigated. A systematic study has been made of the influence of substrate temperature Ts on the structural, electrical, optical and residual stress properties of GZO films. An increase in Ts resulted in a beneficial effect on the crystallinity, electrical conductivity and transmission in the visible (VIS) range regardless of the type of substrate. The minimum resisitivity for GZO on glass and COP substrates was as low as 5.0μΩm and 5.8μΩm, respectively. For all the GZO films with average optical transmission above 90% in the VIS region, with increasing T_s, the optical absorption loss in the visible range decreased according in order of increasing Hall mobility. All the GZO films were found to be compressively stressed. The residual stresses, evaluated from the XRD spectrum, in GZO films on glass substrates are a decreasing function of T_s, whereas they are an increasing function of T_s for GZO films on COP substrates. This finding indicates that for the GZO films on COP substrates deposited at higher temperature, thermal stress is dominant.

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Fully self-aligned oxide-semiconductor field-effect transistors have been investigated. In this transistor process, layout patterns of the gate, source and drain electrodes are determined by the first patterning of gate electrode. From a viewpoint of this concept, 8X8 active-matrix back-plane was fabricated. Transparent electrodes of source and drain are also tested by assuming a liquid crystal display, organic electroluminescence display and electronic paper. Obtained field-effect mobility of the transistor was 5 cm²/Vs. This device concept is effective for a flexible display, where, its substrate will be deformed during thermal process.

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Precise assembly of photo-functional molecules on dendritic phenylazomethine (DPA) was demonstrated. We previously reported the precise assembly of metal ions on dendritic phenylazomethine in stepwise radical fashion. Triphenylmethylium tetrafluoroborate (TPMBF₄) could be coordinated to the imine group of DPA, which allows for control of the number and position of organic molecules in DPA. As one of the applications of an organic molecular assembly, TPM⁺ derivatives holding a photo-functional molecule, azobenzene (Azo-TPM), were incorporated into DPA stepwisely.

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We fabrucated bilayer organic light-emitting diodes (PLEDs) consisting of a diamine derivative (α-NPD) and aluminum(III) bis(2-methyl-8-quinolinate)4-phenylphenolate (BAlq) and investigated their EL properties depending on BAlq's thickness and a kind of cathode metal. Since the OLEDs showed EL spectra including both α-NPD and Balq₃ emissions, we discussed the recombunation mechanism of OLEDs from the ratio of α-NPD and Balq3 emissions. The α-NPD/Balq₃ OLEDs have two recombination zones in α-NPD and BAlq layer, so that electrons are injected into α-NPD layer. To our surprise, when Al with a poor electron injection is used as the cathode, α-NPD content was found to increase as compared with the use of LiF/Al in spite of decreasing electron current. Electron injection into α-NPD was thought to be one of degradation factors.

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We have fabricated yellow organic light-emitting devices (OLEDs) with a new fluorescent small molecules, 3-(N,N-bis(9,9,9',9'-tetraethyl-2,2'-difluorene-7-yl))aminoperylene 1. The yellow dopant 1 was doped into the host material, tris(8-hydroxyquinolinolato) aluminum (Alq₃), with various doping concentration. At 1wt% of the concentration, the device showed the highest efficiency 4.05 % at 100 cd/m². Commission Internationale de I'Ecairage chromaticity coordinates (CIE) of the yellow emission of the device at 100 cd/m² was (0.42, 0.55).

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The evaporative spray deposition using ultradilute solution (ESDUS) technique enables layer-by-layer deposition of polymer semiconductors. In this study we prepared bulk heterojunction type photovoltaic cells composed of blend film of a polythiophene and a fullerene derivative by ESDUS. The bilayer structure of a polythiophene film without fullerene and the blend film brought about significant improvement in the device performance probably due to the electron blocking at the polythiophene film. Though the device performance of the cells prepared by ESDUS were lower than that prepared by spin-coating, it can be understood in terms of the larger polymer domain observed in the blend film prepared by ESDUS than the spin-coat film.

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We report the optical writing in the liquid crystal (LC) cell with a photo-crosslinkable polymer alignment surfaces. Double-faced writing is successfully demonstrated in a guest-host mode LC cell by exposing the cell from both sides with an unpolarized UV light. Different LC alignment patterns are performed on both alignment substrates. Written images can individually be visualized when a polarizer is replaced in front of and behind the cell. Logical operations for two written images are also obtained when the LC cell is set between the polarizer and anarizer.

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Ferroelectric liquid crystals (FLCs) are attractive mesogenic phases because of their unique characteristics such as high speed response. Since the helical structure of the FLC depends strongly on temperature, it is important to control it for the device application especially using the helical structure. In this study, we investigate the temperature dependence of the helical structure in polymer-stabilized FLCs (PS-FLCs) in terms of optical rotatory dispersion (ORD) and circular dichroism (CD). It is found that the helical structure of PS-FLC can be controlled over a wide range of temperature by polymer stabilization.

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Fabrication and characterization of a flexible and transparent upconversion display made of a composites of YF₃: Er³⁺/Yb³⁺ nanoparticles and polymer matrices. To decrease the light scattering loss, the refractive indices of them were adjusted between the particles and polymers in visible wavelength range. The composites were prepared by an UV polymerization of a monomer mixture dispersed with the particles. The obtained materials are flexible and highly transparent as a transmittance of 80 % for a sample with 1 mm thickness at 589 nm. The fabricated flexible and transparent composite sheets showed green upconversion luminescence under a 980-nm excitation. A luminescent graphic on the bent surface of the display drawn by scanning an IR pump laser was clear and bright enough to be visible in ambient room lighting conditions.

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