SiO_2溶胶及其静电自组装薄膜的制备

Preparation of Silica Sols and Anti-Reflective Films with Electrostatic Self-Assembly Multilayer Method

采用HCl催化、NH3 ·H2 O催化、HCl与NH3 ·H2 O分步催化三种途径制备了SiO2 胶体 ,用透射电镜观察了胶体粒子的形貌 .用静电自组装 (ESAM)法制备了聚电解质PDDA与SiO2 胶体粒子的有机 /无机复合光学薄膜 .实验结果表明 ,用HCl催化制备的SiO2 透明溶胶不适合于用ESAM法制备薄膜 ,用HCl与NH3 ·H2 O分步催化以及用NH3 ·H2 O单独催化制备的SiO2 胶体适合于用ESAM法制备光学薄膜 .薄膜的透射电镜微观察结果表明 ,以HCl与NH3 ·H2 O分步催化的SiO2 胶体制备的PDDA/SiO2 薄膜为连续结构 ,NH3 ·H2 O单独催化的为颗粒堆积 .研究了薄膜透光率与薄膜层数的关系 ,考察了薄膜的机械强度 .结果显示 ,以NH3 ·H2 O单独催化的SiO2 胶体制备的光学薄膜的增透效果较好 。

Silica sols were prepared by hydrolysis of Si(OC 2H 5) 4 (TEOS) using HCl, NH 3·H 2O, HCl/NH 3·H 2O as catalyzers, and the different granularities of SiO 2 sols which catalyzed by HCl first and then NH 3·H 2O have the same terminal pH value were prepared. The silica colloidal particles were investigated with Transmission Electron Microscope(TEM). The results showed sol catalyzed by HCl possesses very little particle, catalyzed by NH 3·H 2O has particle configuration, catalyzed by HCl/NH 3·H 2O possesses consecutive configuration. Poly(diallyldimethylammonium chloride)(PDDA) and SiO 2 nanoparticulate complex thin films were prepared by electrostatic self-assembly multiplayer (ESAM) method. After assembling films, thin films surface conformation was observed with Electron Microscope and their transmittance was tested with 721 Spectrophotometer. The results showed that the silica sol catalyzed with HCl is not good for the fabrication of ESAM films and the silica sol catalyzed with HCl first and then NH 3·H 2O or by NH 3·H 2O only are very suitable for ESAM film fabrication. TEM data indicate that the microstructure of PDDA/SiO 2 prepared from silica sol catalyzed with HCl first and then NH 3·H 2O is consecutive and that the microstructure of PDDA/SiO 2 prepared from silica sol catalyzed by NH 3·H 2O only is particulate-parking like. The dependence of the transmittance of assembled films on the bilayer number of the films and the anti-scratching properties of the films were investigated. The results show that PDDA/SiO 2 films prepared from silica sol catalyzed by NH 3·H 2O only possess higher transmittance but lower anti-scratching properties. The effect of granularity of sols on optical performances of the thin films was studied, results showed the less the granularity of sol, the better the optical performances. For the sake of improving the light transmittance of films, we can reduce the granularity of sol, but it may play down its mechanical damage resist intensity.