微乳-水热法制备具有自清洁功能的TiO_2薄膜

Self-cleaning TiO_2 Film Prepared by Microemulsion-mediated Hydrothermal Method

采用热陈化微乳液及浸渍-提拉技术,制备了具有自清洁功能的TiO2薄膜。考察了微乳液中表面活性剂十二烷基苯磺酸(DBS)的用量对TiO2薄膜的表面形态和微观结构的影响。进而对合成的TiO2薄膜的光催化活性、光致亲水性能及实际环境中的自清洁效果进行了测试评价。随着表面活性剂DBS用量的增加,微乳液中的分散质点尺寸减小,但热陈化后所获得的TiO2粒子表现出凝集现象。在DBS用量为0及58 mg/L时,所获得薄膜表面较为平整,由15～20 nm大小的TiO2粒子组成。这些薄膜在无紫外光照射时,水接触角增大的速度较慢,并且在紫外光照射下能迅速恢复其超亲水性能。将薄膜置于室外25 d后其表面无灰尘粘结,水接触角由原来的0°增大至14°～18°。当DBS用量为580 mg/L以上时,薄膜表面起伏不平,粗糙度过大,对应TiO2薄膜光致亲水性能较差,室外放置25 d后,水接触角由原来的0°增大至46°～48°。

Self-cleaning TiO2 films were prepared by hydrothermally treating a microemulsion followed by dip-coating. Effect of the amount of surfactant dodecylbenzenesulfonic acid（DBS） in the microemulsion on the surface morphology and microstructure of TiO2 film was investigated. Photocatalytic activity, photo-induced hydrophilicity and self-cleaning efficiency of the synthesized TiO2 films were evaluated. With the amount of DBS increases, the size of the dispersed TiO2 particle decreases, but the particles tend to agglomerate after hydrothermal treatment. When the amount of DBS is in the range of 0 and 58 mg/L, the resultant TiO2 films consisted of particles with 15~20 nm in diameter are quite smooth. The water contact angles of those films kept in dark increase slowly and their superhydrophilicity can be quickly recovered after irradiation by UV light. The surfaces maintain clean when the films are exposed to outdoor atmosphere for 25 days with their contact angles increasing from 0° to 14°~18°. When the amount of DBS is increased to beyond 580 mg/L, the surfaces of the films become rough and show poor hydrophilicity. The contact angles of the surfaces exposed to outdoor atmosphere for 25 days increase from 0 to 46°~48°.