Films of poly[4-(2-methacryloylethoxy)azobenzene] irradiated with linearly polarized light induced homogeneous alignment of liquid crystals (LC) like a rubbed polyimide film, because of surface anisotropy generated by photoreorientation of azobenzene moieties. Films annealed before irradiation needed more exposure energies of incident light to induce homogeneous LC alignment, than as-cast films. And also photo-rewriting from the initial LC alignment required a large energy to change, in the case of films contacting with LC layers. While a film without LC layers during irradiation caused photo-rewriting of LC alignment at an extraordinarily small energy (10mJ cm^-2).

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We developed new photo alignment materials based on chalconyl structure with high sensitivity to near UV light. Poly(4-methacryloyloxy chalcone), PM4Ch, and its derivatives exhibited good LC alignment upon near UV exposure. The photoreactivity of chalconyl structure was high because due to longer wavelength of UV absorption. The high sensitivity of PM4Ch, compared with Poly(4′-methacryloyloxy chalcone), PMCh, could be explained by the suppression of isomerization and/or by the alignment capability of the side chain structure.

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Ferroelectric liquid crystals (FLCs) exhibit spontaneous polarization and show a response to change in the electric field Switching of this field causes a reversal in the direction of polarization. Here we report in-situ photopolymerization behavior of FLC monomers and image storage using bistable switching by applying electric field. Polymerization behavior was considerably affected by the length of alkyl spacer and structure of functional groups.

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We have studied the electro-optical properties in Polymer Network Liquid Crystal Displays which are composed of a three-dimensional polymer network formed in continuous liquid crystal layers prepared by photo-polymerization induced phase separation processes. In view of the behavior in the orientation of the liquid crystal molecule at the polymer's surface, it can be clarified that the electro-optical properties are strongly governed by the polymer. By a combination of two different characteristics of the polymers with respect to a temperature dependence, a variation in the driving voltage for a temperature change can be improved.

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Electrooptical properties of a polymer/LC grating, which is fabricated by UV irradiation using a mixture of liquid crystal and prepolymer, have been investigated. The diffraction light can be easily controlled by an applied voltage. The response times depend strongly on the applied voltage. On the other hand, recovery times depend slightly on the applied voltage. The response and recovery times around tens of millisecond have been achieved for a lower driving voltage (10V). Experimental results also show that the high diffraction efficiency of 30% for the 1st-order and good extinction ratio over 60:1 are obtained. The groove depth which influences the diffraction efficiency, has also been measured and discussed in various fabrication conditions.

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Newly synthesized polyimide possessing NLO chromophore as a side chain has a good solubility and is stable to 320°C. Polyimide Langmuir-Blodgett (LB) films were prepared by the precursor method. The differences of multilayer structure between the precursor and the polyimide LB films were analyzed by means of Ellipsometry.

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A new second-order nonlinear optical (NLO) polyimide (PI) with high thermal stability has been developed The PI was prepared by the ring-opening polyaddition of 4, 4′-(hexafluoroisopropylidene)diphthalic anhydride with a new diamine with two Disperse Red-I units, followed by poling during andafter the thermal imidization process. The glass transition temperature of PI was 182°C. The second harmonic coefficient (d₃₃) of PI at the wavelength of 1.06μm was 116pm/V (278.6×10^-9 esu) and remained unchanged at elevated temperatures. The corona poling process of the NLO substituted poly(amic acid) to the PI was also studied in detail by measuring the second harmonic generation (SHG) from the polymer films.

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A negative-working photosensitive polymer based on polycarbodiimide (PCD) and {[(4, 5-dimethoxy-2-nitrobenzyl)oxy]carbonyl}-2-methylpiperidine (1) as a photoamine generator(PAG) has been developed The end-capped PCDs with number average molecular weights of 1500 and 2500 were prepared by polycondensation of tolylene 2, 4-diisocyanate (TDI) in the presence of m-tolyl isocyanate and 3-methyl-1-phenyl-2-phospholene-l-oxide as an end-capping agent and a catalyst, respectively. PCDs were amorphous and soluble in common organic solvents, such as toluene, chloroform, and cyclohexanone. Thermo-gravimetry of the polymers showed good thermal stability, indicating that a 10% weight loss of the polymers was at 480°C in nitrogen. The PCD films were transparent above 360nm. The PCD containing 1 showed a sensitivity of 225mJ/cm2 and a contrast of 1.5, when it was post-baked at 90°C for 90sec, followed by development with toluene at 25°C

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Fully imidized and solvent soluble polyimide films with a polyalicyclic structure were prepared from bicyclo[2.2.2]octane-2, 3, 5, 6-tetracarboxylic 2, 3:5, 6-dianhydrides and aromatic diamines. The optical properties such as optical transparency and refractive indices have been evaluated. These films were entirely colorless, and the normalized transparencies in the visible region were over 86%. The films remained colorless and transparent up to 300°C when heated in air, and 400°C in N₂. The polyimides had an average refractive index range of 1.599 to 1.617. The birefringencies of the BAB-based polyimides were nearly zero.

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Ultraviolet/visible absorption spectra and fluorescence spectra of transparent polyimides derived from 2, 3, 5-tricarboxycyclopentylacetic acid dianhydride (TCAAH) with an aromatic diamine, 4, 4′-diaminodiphenylmethane (DPM), a fluorinated diamine, 2, 2 bis(4-diaminodiphenyl)hexaflu-oropropane (6FdA), and an alicyclic diamine, 4, 4′-diaminodicyclohexylmethane (DCHM) were investigated, as well as their thermal properties. All polyimide films derived from TCAAH showed high transparency in the visible region, i. e., no absorption tail was found above 330nm. The absorption shoulders at 248nm of PI(TCAAH/DPM) and PI(TCAAH/6FdA) are due to the absorption of phenyl groups in the diamine moieties. The fluorescence spectra of all polyimide films studied showed the existence of ground-state complexes. Their excitation wavelength dependence would be due to the existence of various conformation of packing structure. The glass transition temperature, Tg, of these polyimides based on TCAAH lies in the region of 251 to 336°C. These polyimides have main decomposition temperature in the region of 427 to 457°C under the deaerated condition.

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We have synthesized novel photoluminescent aromatic conjugated polymers with liquid crystallinities by introducing liquid crystalline (LC) groups into side chains of poly-jvra-biphenylene (PBP) and poly-para-phenylenevinylene (PPV). The LC group is composed of cyanobiphenyl (CB) or phenylcyclohexyl (PCH) moiety as a mesogenic core. Both types of polymers were fusible and soluble in organic solvents. They exhibited monotropic LC behaviors, i.e., the PBP showed nematic phase in the cooling process, whereas the PPV showed nematic and smectic A phases in the cooling process. Besides, they were fluorescent in the region of 480-540 nm, depending on conjugation length of main chain as well as species of LC side chains. A non-oriented film of the PPV showed electrical conductivities of 10^-5 and 10^-3S/cm before and after iodine doping, respectively. Electrical and optical anisotropies of the present polymers are discussed from advanced multifunctional materials.

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Polyimides are widely used as dielectrics in high density multi-chip module (MCM) wiring systems in order to adjust the thermal expansion between LSI chips and substrates. In these MCMs, Copper is commonly used for vias which interconnects different layers. In these structures, there are some drawbacks which adversely affect the multi-layer wiring system. Among them, a major problem is that in order to get a high wiring density, a large number of vias with a very small via diameter have to be created. However, if there are large number of vias, due to the Z-directional thermal expansion mismatch of Cu and the dielectric, stress concentrated around vias leading to fracture and crank formation in the dielectric. Therefore, in this paper, in order to find a promising dielectric material, to the utilized in MCMs, the Z-directional coefficient of thermal expansion (CTE) of polyimide films prepared with different processing conditions was investigated. The Z-directional CTE of the films was measured by the laser interferometric technique.

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CH₄ plasma CVD films were formed by a reactor with a parallel plate electrode system at a discharge frequency of 13.56MHz with using a mixture gas of CH₄/H₂ and H₄/Ar. The deposition rates were measured as a parameter of gas pressure, and discharge power in order to discuss deposition mechanisms. The effects of O₂ and SF₆ addition in the mixture gases were also examined. Addition of oxygen gas in the mixture gas of CH₄/H₂ enhanced the growth rates, which were proportional to the radiation intensity ratio CH/H_α in the plasma. On the other hand, the addition of oxygen gas in the mixture gas of CH₄/Ar decreased the growth rate. It was observed that oxygen atoms were extracted from the film during the process, however sulfur atoms were doped into the film. These experiments suggested the possibility of film property control.

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Poly(tetrafluoroethylene) (PTFE) and low and high density polyethylene (LDPE and HDPE) plates were surface-modified by the photogafting of methacrylic acid (MAA) using a 400W high pressure mercury lamp. The autohesive strengths for MAA-grafted PTFE, LDPE and HDPE plates were estimated from the tensile shear strength measurements and their autohesive properties were discussed in relation to surface and bulk properties of the grafted layers formed on their substrates. The contact angles which were related with the wettabilities of the modified surfaces increased with an increase in the grafted amount, and then leveled off when the surfaces were wholly covered with grafted PMAA chains. The wettabilities for grafted PTFE plates were improved at a considerably low grafted amount, since the photografting of MAA onto the PTFE plates was most restricted to the outer surface region among the three types of substrates used in this study. The grafted LDPE and HDPE plates possessed high water-absorptivities. The autohesive strengths for grafted PTFE plates immersed in water reached the value equivalent to their adhesive ones. For the grated PTFE plates immersed in an aqueous HCl solution of pH 3 in place of water, the autohesive strength sharply increased in the range of lower grafted amounts. These results suggest that an increase in the autohesive strength can be caused not only by the entanglements of grafted PMAA chains but also by the formation of hydrogen bonding between carboxyl groups affixed to the grafted PMAA chains. On the other hand, in the case of the autohesive strength measurements for Grafted LDPE and HDPE plates, the substrate breaking occurred at higher grafted amounts. The grafted amount at which the substrate failed for grafted HDPE plates was lower than that for grafted LDPE plate because the photografting onto the HDPE plates was more restricted to the outer surface region. It was made clear that the autohesive strength for grafted PTFE plates reached the value equivalent to the autohesive strength and the autohesive strengths for grafted LDPE and HDPE plates exceeded the ultimate tensile strength by heat-pressing the grafted samples with the grafted layers swollen in water.

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It is known that a carbon fiber has a high biocompatibility. The amount of adhered activated sludge was much large when carbon fiber was bathed into an activated sludge. Activity and wet ability on surface of carbon fiber were increased by photo-oxygenation treated at 100°C, 150°C, and 200°C. After the treatment, functional groups including atoms were introduced to surface of carbon fiber. The amount of adhered activated sludge to treated carbon fiber was measured each at 1 minute. The amount of adhered activated sludge was increased with increasing treated temperature. The surface of carbon fiber was analyzed by X-ray photo-electronic spectroscopy (XPS). The ratio of oxygen/carbon atoms on the surface of treated carbon fiber was larger than that of untreated carbon fiber. Functional groups including oxygen introduced into the carbon fiber surface were influenced to the adhesion of activated sludge on carbon fibers and improved in the wet ability.

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This paper deals with the plasma surface treatment of polymers in a low frequency bell jar reactor with non-symmetrical configuration of electrodes. This special configuration of electrodes simulates the industrial surface treatment of polymers i.e. very short treatment times (milliseconds to a few seconds). The physicochemical properties of different polymers modified in such a reactor using ammonia and its mixtures have been investigated. The industrial aim of such treatments were for adhesion improvement in applications such as metallization and immobilization of proteins for the fabrication of immunosensors. The last part of this paper was devoted to the study of the stability of the plasma modified polymers which is an important issue for the industrial development of plasma processes. A pretreatment in a noble gas such as helium was proposed in order to stabilize the extreme surface layer via crosslinking before the functionalization treatment in ammonia plasma. In order to carry out the crosslinking and functionalization process in a one step process, mixtures of He+NH₃ plasmas were studied.

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Five kinds of synthetic polymers, poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA), poly(methacrylic acid) (PMAA), poly(methyl acrylate) (PMA), and high-density polyethylene (HDPE), were subjected to microwave H₂O plasma. In the plasma, the polymers were decomposed, and the formation of methanol in the process was confirmed. The decomposition rate of the polymers in H₂O plasma decreased in the following order: PMMA>PEMA>PMAA>PMA>HDPE. Methanol showed the greatest yield among the organic compounds in the products for the each polymer. The conversion into methanol for respective polymers was in the following ratio: PMMA: PEMA:PMAA:PMA:HDPE=2:1:1:1:0. This result shows good agreement with the total number of methyl group and methoxycarbonyl group (methyl ester) per repeating unit in respective polymers. This result implied that both methyl and methoxycarbonyl groups in the polymers contributed to the decomposition and formation of methanol in H₂O plasma. Other products obtained were acetaldehyde, ethanol, acetone, 2-propanol, and acetic acid.

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Cold-plasma conditions are suitable for producing high concentrations of free radicals even on the most inert polymeric substrates and to etch preferentially amorphous and crystalline zones of polymer surface morphologies. This opens up a novel way for initiation of replica-type graft-polymerization reactions with plasma treated substrates. Use of crystallinity-enhanced and activated natural polymeric surfaces as polymerization initiators is significant since it allows a better understanding of the sterical order of natural polymers and also permits the synthesis of synthetic macromolecules "encoded" by the sterical order of the natural "host" polymer. Template graft-polymerization of acrylonitrile (AN) and styrene (ST) were performed on RF-plasma enhanced-crystallinity cellophane surfaces through plasma-induced polymerization mechanisms. The influence of plasma treatment time on the surface crystallinity of the natural substrates and the presence of ordered synthetic polymeric layers on the host-polymers were investigated by atomic force microscopy (AFM). The presence of surface functionalities on virgin and plasma-treated surfaces were monitored by survey and high resolution X-ray photoelectron spectroscopy (ESCA) and by differential, attenuated total reflectance infrared spectroscopy (ATR-FTIR).

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CFC-113 (Cl₂FC/CClF₂), CFC-12 (CCl₂F₂), and PFC-116 (F₃C/CF₃) were each combined with ethylene (H₂C=CH₂) in plasma copolymerization to deposit polymer films. The relative deposition rate was shown to be CFC-113>CFC-12>PFC-116, which indicates that the presence of Cl may serve to accelerate the polymerization rate. With a C₂H₄ mixing ratio of 1:1, the C-H(stretching vibration) peak of the IR spectrum from the resulting film disappeared for CFC-113/CCl₄, which contains Cl. In comparison, the C-H peak for PFC-116, which does not contain Cl, is still apparent, indicating that an H abstraction reaction took place. The results of thermal stability showed that a weight loss starts at 200°C for polymers deposited by CFC-113 and CFC-12, and at 250°C for polymers deposited by PFC-116. The melting point exceeded 300°C for all polymers, and was in excess of 400°C for PFC-116. Dielectric constant of polymers deposited by PFC-116/C₂H₄, which contains H, was stable at 2.9 regardless of the source gas mixing ratio. Polymers deposited with CFC-113 and CFC-12 demonstrated a decrease in dielectric constant (1.9∼2.1) as the CFCs concentration was increased. These results indicate that polymer films deposited in a plasma copolymerization using monomer gases including CFCs may potentially be used in various applications, such as materials for micro electronic devices.

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In order to develop temperature-responsive dispersing systems, we have grafted poly(N-isopropylacrylamide) (PNIPA), which is a temperature-responsive polymer having a lower critical solution temperature (LCST) at 32°C, onto carbon black (CB) by plasma-induced graft polymerization technique. CB was treated with H₂O and/or O₂ plasma, to which aqueous solution of the monomer (NIPA) was introduced, resulted in simultaneous graft polymerization. The dispersibility of the PNIPA-grafted CB in water at 25 and 35°C was investigated by the measurement of the transmittance of visible light (500nm). The most of the PNIPA-grafted CB showed better dispersibility at 25°C (below the LCST) than at 35°C (above the LCST). In many graft polymerization conditions, CB grafted in 2wt% of the monomer concentration with ultrasonic irradiation at room temperature showed the most clear temperature response of the dispersibility in water.

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Epoxy and alkyd surface was treated by rf plasma in order to make the surface ultrahydrophobic. Two types of sample, stiffened or unstiffened, were used. The surface characteristics were estimated by the contact angle of water, X-ray photoelectron spectroscopy (XPS), Fourier transfer infra-red (FTIR) spectroscopy and scanning electron microscopy (SEM). When the resin was unstiffened, the surface became ultrahydrophobic after CF₄ plasma treatment. The contact angle on the surface was approximately 150°. Many fluorocarbon groups were observed on the surface after treatment. Moreover, the surface had a villas structure with crinkles in a crinkle. Stiffened surface had also many fluorocarbon groups after CF₄ plasma treatment but was merely hydrophobic. The surface, where the contact angle was 110°, was smooth like a mirror. With Ar plasma treatment, the resin surface was merely hydrophobic though the surface had a villas structure. There are two factors for making ultrahydrophobic surface; binding of F atoms or groups and abrading. Since the unstiffened resin has a weak bonding in polymer chain, the surface was easily substituted by F atoms and etched by CF₄ plasma treatment. As a results, the unstiffened surface became ultrahydrophobic.

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The surface structures of ablated rabbit cornea and collagen film were examined using AFM and SEM observations. The surface roughness of the rabbit cornea increased linearly, and then significantly increased as the pulse number increased to 2500. However, the surface roughness of the collagen film increased sharply, and then leveled off as the pulse number increased. Especially, the formation of a conical structure on the dried rabbit cornea and the collagen film was observed, but the formation of the conical structure in situ on the rabbit cornea was not detected. The formation of a conical structure shows that radiation hardening of collagen as a function pulse number has occurred. The presence of hydration in the collagen molecule plays an important role in the surface structure of the cornea during excimer laser ablation.

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The excimer laser ablation lithography (EAL) is a process of direct patterning and developing of a resist film by photodecomposition ablation. Taking advantage of EAL process, we have tried to apply this process to LCD fabrication. As the most fundamental problem for resist materials is the ablation rate, we have examined to measure the ablation rates of many kinds of polymers. Among them the most promising is the polyurethane resin (PU) which is synthesized from toluenediisocyanate and poly(ethylene glycol) derivatives in chlorobenzene solution. The ablation rate at 100mJ/cm² fluence of 248nm is more than 0.05μm/shot, which is the highest value of all the materials that we have examined. Through the investigations of structures of PU, we could elucidate the mechanisms of the high ablation rate, and accordingly the molecular design concept of the ablation resist.

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Polythiophene thin films are prepared from several thiophene derivatives, such as 2, 5-dichlorothiophene(DCT), 2, 5-dibromothiophene(DBT) and 2, 5-diiodothiophene(DIT) by UV laser-assisted deposition (UV-LAD) with 193 (ArF), 248 (KrF) and 308nm (XeCl) beams. Each film prepared by UV-LAD possesses highly oriented fibrous structure called laser induced periodic structure (LIPS). Electric conductivities of some films have increased from less than 10^-7S cm^-1 up to 10^-3S cm^-1 by doping with iodine after UV-LAD. FT-IR, ESCA and UV-vis. spectra show that, although sulfur atoms are eliminated to some extent, polymerization basically occurs at 2(α)-5(α′) positions of the thiophene derivatives by elimination of halogen atoms. For the film prepared by UV-LAD of DIT at 308nm, the average conjugation length is estimated to be corresponding to that of thiophene oligomers consisting of 4±1 thiophene units.

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Coherent and incoherent light sources using rare gas excimers are reviewed from a point of view of post ArF lithography. Present status of electron beam pumped rare gas excimer lasers are reported. Potentialities of rare gas excimer lasers by discharge pumping are discussed. We have obtained laser gain of 2.2x10^-3cm^-1 in Kr discharges which was very close to the threshold gain. It is pointed out that gas excimer lasers are suitable for light sources for next generation lithography after ArF lithography in the 21th century, when a compact excitation method is established. A jet discharge excimer lamps are also discussed from a point of view of an incoherent light source for lithography.

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Excimer-laser processing can be extended to a broader and more diverse range of materials by moving to vacuum-ultraviolet (100-200nm) laser sources such as the molecularfluorine and argon excimer lasers. The 126-nm and 157-nm output wavelengths from the argon excimer and fluorine lasers take advantages of the extremely high photon-energy, the high opacity in most materials, and short pulse duration to minimize thermal loading of target surfaces. The lasers readily drives photochemical interactions. The 126-nm photons induce oxygen desorption and silicon precipitation both in high purity silica glass and crystalline quartz. The 157-nm photons readily etch off the surfaces in vacuum ultraviolet grade silica glass and crystalline quartz.

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