The Preparation of TiO₂ Film by the Sol-Gel Method and Evaluation of Its Self-Cleaning Property.

TiO₂ sol was produced by the sol-gel method through the hydrolysis and the aging of tetrabutyl titanate and the TiO₂ film was obtained by dipping and uniform lifting of the acid-treated and ultrasound-treated clean glass slides into the TiO₂ sol followed by aging, drying, and calcination. The effect of the hydrolysis control agents to the formed sol was researched and the crystalline state, the morphology, and the photocatalytic properties of the products after calcination were characterized. The structural morphology, the contact angles before and after illumination, and the self-cleaning properties of the TiO₂ film were characterized as well. The results showed that by using acetylacetone as the hydrolysis control agent, the formed TiO₂ sol had relatively high stability. The product after the calcination of the TiO₂ sol was of single anatase type with crystalline size of 18-20 nm and it could degrade nearly 100% of methylene blue after 90 min illumination. The formed TiO₂ film is compact, continuous, smooth, and had the properties of super-hydrophilicity (after 30 min illumination due to its contact angle decreasing from 21° to nearly 0°) and anti-fogging capability, which indicated its excellent self-cleaning property.