Polymer waveguides have a potential of achieving the economic requirement for low priced optical devices and of applying novel active devices. The developments of the polymer waveguide materials and their applications have been investigated since 1990s. The remarkable progress on the polymer waveguides is expected to realize acceptance of the polymer devices in the optical communication networks. We review the recent progress on the polymer waveguide materials in addition to the characteristics required for the waveguides.

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Three new emitting materials, featuring a 2, 2'-bi-[1, 3, 4]-thiadiazole core, for the use in organic electroluminescent devices (OLEDs) have been synthesized and tested. Color tuning from blue to red was achieved by attaching various electron donors to the basic skeleton. The obtained maximum brightness for blue, green and red were 2080 cd/m², 56000 cd/m² and 1070 cd/m², respectively.

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Intracellular localization of sparfloxacine (SPFX), a fluoroquinolone antibacterial agent, was studied using human buccal mucosa cells by fluorescence microscopy and microspectrofluorometry. Green fluorescence of SPFX was observed in the plasma membrane region, cytoplasmic patch areas and nuclear region. Since SPFX behaves as a hydrophobic fluorescent probe, the feature of fluorescence implies that SPFX is accumulated in hydrophobic regions such as membrane structures and nuclei of the cells. In addition, SPFX-photosensitized damage of lysosomal membranes in the cells was evaluated by detecting leakage of a lysosomal enzyme β-galactosidase, using a fluorogenic substrate fluorescein-di-(β-D-galactopyranoside) (FDG). When SPFX in the cells, which took up FDG with SPFX in advance, was excited with UV-A light, fluorescence emitted from fluorescein produced as enzymatic cleavage of FDG with a lysosomal enzyme β-galactosidase was detected in the cytoplamic region. This observation implies that lysosomal membrane damage on SPFX-photosenseitization caused leakage of β-galactosidase from lysosomes. The present results indicate that lysosomes are one of possible intracellular targets of SPFX-photosensitization.

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In order to prepare hydrophobic and hydrophilic surfaces, silane coupling treatment with hexamethyldisilazane (HMDS) and exposing to oxygen plasma are carried out to silicon oxide substrates, respectively. Surface force measurement indicates that the attractive force F of the AFM tip is more sensitive to surface energy variation of the solid surface. The adhesion work W mainly depends on polar component of surface energy. Positive correlation between elastic energy E_e of the cantilever tip and adhesion work W can be confirmed. By using two kinds of tips which have different component values of surface energy, surface property in lithography process can be analyzed.

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We have modified nitrogen-containing polymer surface by quaternization of nitrogen atoms with halogenated hydrocarbons. Previously, we used a few kinds of alkyl halides for surface quaternization. In this study, we varied the reagents for poly(4-vinylpyridine) (PVPy) quaternization and investigated the luminescence property of the surface quaternized PVPy. A variety of the quaternization reagents, halogenated hydrocarbons, revealed to be applicable for the quaternization to produce longer wavelength luminescence than the luminescence of non-quaternized PVPy films. The surface morphology of the films were also observed.

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The refractive index modification of polysilane films by the Ultra-Violet (UV) light irradiation was investigated. Poly(methylphenylsilane) (PMPS) and other polysilanes involving phenyl group attached directly to a silicone atom showed high refractive index (n_init ∼ 1.70) and very large refractive index reduction (Δn = −0.14) at λ = 633 nm compared with alkyl substituted polysilanes. The effective reduction in these polysilanes was found to be caused by the elimination of phenyl substituents in addition to the shortening of the σ-conjugation due to the photo-oxidation of silicon backbone for shorter wavelength UV light exposure. Thus, UV-exposed polysilanes turned to almost the same siloxane-like structure consisting of Si-O-Si backbone with alkyl substituents, and their refractive indices converged to a lower value of about 1.55. These results indicate that the molecular design of the side groups to enhance the initial refractive index can expand the dynamic range (Δn) in the refractive index modification of the polysilane film.

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A new positive-working low-molecular-weight photoresist has been developed. The photoresist consisted of the matrix, tetra-C-methylcalix[4]resorcinarene (p-t-BM-C4-R) in which the OH groups were protected with tert-butoxycarbonylmethyl groups (protecting ratio: 27 ∼ 60%), and a photoacid generator (PAG), 5-(propylsulfonyloxyimino-5H-thiophen-2-ylidene)-2-methylphenyl-acetonitrile (PTMA). The p-t-BM-C4-R (protecting ratio: 40%) containing PTMA (2 wt%) showed a high sensitivity (10 mJ/cm²) and a contrast 11 after the irradiation with g-line, post-exposure baking at 120 °C at 60 sec, and developing with 2.38 wt% tetramethylammonium hydroxide aqueous solution (TMAHaq) at 20 °C for 10 sec.

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Enol ether derivative of poly(5-vinyluracil) released completely the tert-butyl groups above 195 °C and gave poly(5-vinyluracil). The resist film as spin coated from chloroform solution containing photo-acid generator released completely the tert-butyl groups after UV light (250 nm) irradiation followed by post exposure baking. Solubility of the obtained polymer containing uracil unit was significantly different from the original polymer containing alkoxy units in both polar (TMAH aq for negative) and nonpolar (anisole for positive) solvents as developer. The results were compared with values of the poly(6-vinyluracil) derivative, and the difference were attributable to the difference of the polymer structures.

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Quantum yields for decomposition of a series of i-line sensitive photoacid generators were evaluated in acetonitrile solution or in polystyrene films. Sulfonate ester derivatives of N-hydroxynaphtaleneimide, fluorenone oxime, and thioxanthone oxime were investigated. Photolysis degree of photoacid generators was successfully estimated by UV or in situ FT-IR spectral changes. First-order decomposition profiles were observed for all photoacid generators on i-line irradiation. Quantum yields for decomposition (Φ_d) were calculated based on the rate of decomposition and molar absorption coefficient of photoacid generators. The Φ_d values were determined by using fluorenylideneimino p-toluenesulfonate as a standard. The Φ_d values of photoacid generators derived from fluorenone oxime and thioxanthone oxime were similar to those of conventional photoacid generators. The relationship between thermal stability of photoacid generators and those Φ_d values was also discussed.

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We have investigated effects of protecting group of fluoroalcohol as alkaline solubility on lithographic performance for the designing of chemical amplification positive-tone resist system. Preparing three different protecting groups (methoxymethyl: MOM, ethoxymethyl: EOM and fluoroethoxymethyl: FEOM) of norbornene hexafluoro-isopropanol (NBHFA) polymers and resists consisted of these polymers, we have evaluated optical properties, dissolution rates with developer, exposure sensitivities and resolution. These polymers showed a good pattern profile and high resolution. In addition, as compared with NBHFA-MOM and -EOM polymers, NBHFA-FEOM polymer displayed a good absorption coefficient at 157 nm.

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