Ag-TiO2多孔薄膜及其非紫外光辐照下的超亲水特性

采用溶胶凝胶法，以钛酸丁酯为前驱体、硝酸银络合物为银源、聚乙二醇2000（PEG2000）作为结构导向剂，制备超亲水多孔Ag-TiO₂复合薄膜。用X射线衍射仪、X射线光电子能谱仪、扫描电镜、原子力显微镜表征薄膜晶相结构、化学成分以及表面形貌。根据静态水接触角、动态润湿时间、超亲水长效稳定性综合评价不同Ag含量及PEG2000添加量薄膜的超亲水性能。研究发现，掺杂Ag与PEG2000对薄膜在非紫外光下的超亲水特性具有协同作用，掺杂Ag明显提高薄膜动态润湿速度及可见光响应，表面粗糙多孔结构有利于避光条件下的长效超亲水特性。Ag含量10%、PEG2000掺杂量5%的Ag-TiO₂复合薄膜在自然光条件下已具备优良的超亲水性能；水滴0.2 s内即可在表面完全铺展到0°；避光条件下保存，超亲水时效性可达到30 d以上。在可见光活化下即可强化超亲水性能，具有良好的防雾效果。

Ag-TiO2 porous thin film and its superhydrophilic properties under visible light

Superhydrophilic Ag-TiO₂ thin films were prepared by the sol-gel method using titanium-n-butoxide as TiO₂ precursor, silver nitrate as silver source, poly(ethylene glycol) (PEG2000) as structure directing agent. As-prepared composite thin films were characterized by X-ray diffraction, X-ray photoelectronic spectroscopy, scanning electron microscopy and atom force microscopy. The superhydrophilicity of Ag-TiO₂ thin films with different Ag and PEG2000 contents were evaluated in terms of static water contact angle, wetting time and long-term stability. Ag-doping significantly improved response to visible light and shortened wetting time, and porous surface with high roughness favored long-term superhydrophilicity. The Ag-TiO₂ thin films with 10% Ag doping and 5% PEG2000 content showed excellent superhydrophilic properties under natural light conditions. Water droplets could fully spread on the surface within 0.2 second with static water contact angle of 0°. Superhydrophilicity was maintained for more than 30 d when the thin films were stored in dark place. Superhydrophilic properties were enhanced when the films were irradiated under visible light. The composite Ag-TiO₂ thin films showed excellent anti-fogging effect.