TiO₂ nanocrystalline electrodes were prepared from titanium tetra-n-butoxide modified with double hydrolysis inhibitors, i.e., benzoylacetone (BzAcH) and polyethylene glycol (PEG), in methanol and ethanol. The correlation between surface structure of the TiO₂ electrodes, preparation conditions, and photovoltaic properties of solar cells using the TiO₂ electrodes was investigated. The TiO₂ electrodes with large roughness value and narrow size distribution of nanocrystals (about 8 nm) were prepared by the addition of BzAcH/PEG in ethanol-rich solvent.The amounts of adsorbed dyes for these TiO₂ electrodes were larger than that without PEG. The performance of the solar cell fabricated using the TiO₂ electrode improved as the amount of PEG increased.

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In a radical copolymerization of n-butyl acrylate (NBA) with methyl methacrylate (MMA) or methacrylic acid (MAA) in n-butyl acetate at temperatures between 120 and 170°C by the use of an autoclave, the effect of a rise in the copolymerization temperature on the amount of residual monomers and composition, monomer sequence distribution, and other characteristics of the resulting copolymers were studied. The amounts of residual MMA increased with increasing MMA fraction and decreasing initial monomer concentration when the reaction took place at 150°C or above. These results suggested that equilibrium polymerization occurred at the high temperature even under the conditions for the preparation of low molecular weight resins with high conversion. The composition of copolymers obtained over a period of time at the high temperature was almost kept constant and was closed to that of fed monomers during the polymerization. The reaction of poly (MAA-co-NBA) obtained at higher polymerization temperature with tetra-functional epoxy compound gave films with higher cross-linking density, as compared with those which were prepared with poly (MAA-co-NBA) obtained at lower temperature. ¹H-NMR measurement of poly (MMA-co-NBA) converted from poly (MAA-co-NBA) revealed that a raise in polymerization temperature decreased the fraction of MMA diad, which is equivalent to MAA diad in the copolymers. The low fraction of MAA diad was considered to be closely related to the higher cross-linking density because mutually adjacent carboxyl groups in MAA diad were more sterically hindered from reacting with the epoxy compound.

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