KONG Xia, HU Yawei, HE Huirong
(College of Chemistry & Chemical Engineering, Shaanxi University of Science & Technology, Xi’an 710021, Shaanxi, China)

Abstract: ZnO/TiO₂ composite films were fabricated through sol-gel method. The phases and surface morphologies of the ZnO/TiO₂ films were characterized by XRD and SEM. The wettabilities of ZnO/TiO₂ films were measured by a drop shape analyzer after being modified with the low surface energy material 1 H, 1 H, 2 H, 2 H- perfluorooctyl trichloro silane. The effect of TiO₂ content on the wettability of ZnO film under UV irradiation was investigated. The result demonstrated that the molar fraction of TiO₂ loaded on ZnO film had a significant effect on the wettability conversion. The water contact angles of ZnO/TiO₂ films reduced and the hydrophobility switched to hydrophicility after 30 min UV illumination. The wettability conversion of ZnO/TiO₂ films accelerated with the increase of TiO₂ content. A rapid switch of wettability occurred on the surface of ZnO/TiO₂ composite with TiO₂ content of 7.5% (molar fraction), which converted to superhydrophilic after 30 min UV illumination. With the TiO₂ content increased to 10%, the conversion of wettability decelerated.

Key words: ZnO; sol-gel method; wettability conversion