不同导电基底对TiO2薄膜光致亲水性的影响

分别在导电铝合金片(Al)和具有阳极氧化铝层的非导电铝片(AAO/Al), 以及铟锡氧化物导电玻璃(ITO/glass)和普通非导电玻璃(glass)表面通过提拉法制备出TiO2/Al和TiO2/AAO/Al, 以及TiO2/ITO/glass和TiO2/glass两组TiO2薄膜样品, 通过测试紫外光照下水滴接触角的变化考察TiO2薄膜的光致亲水性. 结果表明, 相对于TiO2/Al2O3/Al, 基底导电的TiO2/Al表现出较好的光致亲水性能; 而相对于TiO2/glass, 基底导电的TiO2/ITO/glass表现出较差的光致亲水性能. 分析认为, Al和ITO两导电基底和TiO2薄膜间的不同电子转移方向影响TiO2薄膜的光致亲水性能, Al片提供电子给TiO2有助于提高以光生电子为主要初级活性物种的光致亲水性, 而ITO接受TiO2的光生电子, 导致光致亲水性的下降.

Influence of Conducting Substrates on the Photoinduced Hydrophilicity of TiO2 Films

TiO_2 films on Al alloy (Al), anodic aluminum oxide (AAO/Al, formed at the surface of Al alloy), indium-tin oxide glass (ITO/glass) and glass were prepared by a dip coating method. The measurement of water drop contact angle under UV irradiation shows that TiO_2 films on the conducting Al substrate have a higher activity for photoinduced hydrophilicity than that on the non-conducting AAO/Al substrate. Alternatively, TiO_2 films on the conducting ITO/glass substrate have a lower activity for photoinduced hydrophilicity compared to TiO_2 films on the non-conducting substrate glass. These observations are due to electron transfer between TiO_2 and substrates. Al acts as an electron donor and donates electrons to TiO_2, which results in an increase in the photoinduced hydrophilicity of TiO_2 film.ITO accepts the photogenerated electrons, which results in a decrease in the photoinduced hydrophilicity of TiO_2 films.