TiO_2纳米膜表面结构形态特征

Surface Structural Morphology of TiO_2 Nano-Films

采用反胶束法制备TiO2纳米溶胶,用浸渍提拉法在不同的条件下制备了三种TiO2多孔纳米薄膜,并利用AFM、SEM、XRD等方法对膜表面结构物理化学特性进行表征.结果表明三种膜基本上由粒径约为59nm的纳米粒子以不同的方式堆积而成,溶胶刚生成时浸提一次,干燥、焙烧得到膜上纳米粒子分布均匀,所生成的二次粒子粒径最小,二次粒子形成的二次表面粗糙度最小,浸提10次得到膜上纳米粒子间存在较丰富缝隙结构,二次粒子粒径及其形成的表面粗糙度较大,而溶胶制备好陈化6h后浸提得到的膜上二次粒子粒径最大,表面粗糙度最高。由分形理论估算得到三种膜的分形维数分别是2.22、2.20和2.27XRD测试表明,膜上TiO2为锐钛矿晶相.这些结果表明,采用不同制备步骤得到的膜,其表面结构形态存在较大的差异.

A TiO2 reverse micelle solution was prepared by mixing water-Triton X-100-cyclohexane reverse micelle with a mixture of titanium isobutoxide and isopentanol, and then three TiO2 films supported on glass have been made by dip-coating in the reverse micelle solution under different performance. Film A was dipped once immediately in the as-prepared reverse micelle solution, film B was dipped ten times in the as-prepared reverse solution, film C was dipped in the reverse micelle solution which had been aged six hours. The morphology of the films was studied by XRD, SEM, and AFM. The results showed that on the film A TiO2 nanometer particles distributed homogenously, but on film B and C the nano-particles were aggregated in different fashions, and formed second particles like island, the surface roughness of the film surface increased obviously, especially film C was the most rough one. According to the fractal geometry analysis, all films surface structural morphology have a properties of fractal structural morphology with estimated dimension 2. 22, 2. 20, and 2. 34, respectively.