TiO_2薄膜的亲水性及光催化自清洁效果

以溶胶-凝胶法为基础,在普通玻璃表面制备了具有纳米尺寸气孔、纳米及微米尺寸复合气孔结构的TiO2薄膜或TiO2/SiO2复合薄膜,并考察了它们的亲水性能及表面经空气中灰尘污染后,其超亲水性能在紫外光照射下的恢复能力。所有纯TiO2薄膜于制备后测试的表面水接触角均达到0°。SiO2的掺杂量较小（10%）时,SiO2的掺入增大了薄膜的水接触角,但随着SiO2掺杂量的增大,接触角减小,可达到超亲水效果。表面污染的薄膜经紫外光照射后,其超亲水性的光致恢复能力基本不受前驱体溶胶的陈化时间、SiO2掺杂浓度、表面形态的影响,但与薄膜的光催化活性有关。4层以上的薄膜或带有SiO2中间隔离层的薄膜由于可以抑制玻璃基底中Na＋扩散至薄膜表面,光催化降解灰尘污染物的能力较高,紫外光照射后均能恢复其超亲水性能。

Hydrophilicity and Photo--Catalytic Self--Cleaning Function of TiO2 Films

Nanosize pore, nanosize combining maerosize pore modified TiOz films and TiOz/SiOz compos- ite film were prepared on glass substrate by sol--gel method. The hydrophilicities of the films and its recovery capabilities under irradiation of UV light were investigated for the as--prepared films and the films contaminated outdoors, respectively. All the as--prepared TiO2 films show water contact angle of 0°. The contact angle for TiO2/SiO2 composite film is high as compared with the pure TiO2 film when SiO2 concentration is low （10%） and decreases when SiO2 doping amount is further increased. The recovery capability of superhydrophilicity under irradiation of UV light is not influenced by the aging time of the precursor sol, mole fraction of SiO2 and the surface morphology of the film. It depends on the photocatalyric activity of the TiO2 film. For the TiO2 films prepared by repeating coating process over 4 times and the film fabricated with SiO2 interlayer, the superhydrophilicity can be restored by UV light irradiation because these films can suppress the diffusion of Na＋ from the glass substrate to the surface of the film and perform higher photocatalytic activity to the dust contamination.