纳米多孔SiO_2-TiO_2复合薄膜的制备及研究

Preparation and investigation of nanoporous SiO_2-TiO_2 composite film

采用溶胶-凝胶技术，以表面活性剂十六烷基三甲基溴化铵CTAB为模板剂，乙酰丙酮作为钛的水解控制剂，通过钛和硅醇盐的分步水解得到均匀的SiO2-TiO2复合溶胶，通过提拉制备出具有纳米多孔结构的复合薄膜．实验结果表明，多孔薄膜中的钛离子形成了Si—O—Ti键的孤立四配位形态，使薄膜具有复合型钛离子的催化效果，并且有介孔结构．随TiO2含量的增加，薄膜仍具有较好的透光性（可达到85％以上）．通过对实验条件的调节，可实现对薄膜纳米结构的人工控制，形成的多孔薄膜折射率在1．2～1．4之间连续可调．

Nano-porous composite films with high transmittance （above 85 % ） have been prepared at ambient pressure by sol gel technique. Composite sols were prepared from the precursor TEOS, TPOT and template CTAB and so on by ＂order hydrolysis＂ of the metal alkoxides derived from sol-gel process. Films are obtained via dip-coating process. The results show that the isolated and tetrahedrally coordinated Ti^4 ＋ which formed Ti-O-Si bondon the pore inner surface of the framework. The result also implies that this kind of nano-porous composite should exhibit the catalytic effects from isolated titanium ions and had mesoporous structure. The nano-porous structures of the films can be controlled artificially and refractive index of the films can be adjusted from 1.2 to 1.4.