The following characteristics were investigated for a surface of the outermost layer of FezOs formed on vacuum evapolated thin film iron on alumina substrates after thermal oxidation. (1) Electric resistance of Fe2O3 thin films remained unchanged after 1000 hours at 40% relative humidity at room temperature. (2) Sensitivity to humidity remained invariant after 60 minutes soaking in boiled distilled water. (3) The ratios of response time at desorption and adsorption for electric current change to humidity change were 1.58_??_1.97. (4) It was found that the adsorption velocity is nearly equal to the desorption velocity at 50% relative humidity, but below this humidity the adsorption velocity is much bigger than the desorption velocity, while above this humidity the desorption velocity is much bigger than the adsorption velocity. (5) Theoretical equation for isothermal line is
i(H, T)=Aexp (BHT) (273K<T<373K) where i (H, T) is electric current, H is relative humidity, T is absolute temperature, and A and B are constants.
Titanium dioxide was encapsulated in poly-methylmethacrylate (C-MMA-TiO2) by the encapsulating polymerization process, and its photoconductivity was investigated. As a result, the photoconductive properties of C-MMA-TiO2are found to be considerably enhanced as compared with TiO2 and TiO2/ polymethylmethacrylate dispersion composite material (TiO2/PMMA). Further the dark current-voltage characteristics and the rise and decay characteristics of the photocurrent were studied, and the photoconductive mechanisms are discussed.