碱性条件下多孔SiO_2增透膜的结构控制

Structural control of porous silica thin films under alkaline condition

以正硅酸乙酯为无机前躯体,在碱性条件下,采用溶胶-凝胶技术,用浸渍法提拉工艺制备了二氧化硅透明多孔薄膜。详细研究了催化剂的含量对溶胶及膜层性能的影响。利用Netzsch热分析仪研究了干凝胶在干燥过程中的热稳定性,用扫描电子显微镜(SEM)对样品薄膜的形态结构进行了表征以及用分光光度计考察了薄膜的增透性能。结果表明,氨用量的增加对溶胶黏度的影响不大,但缩短了溶胶达到最佳涂膜效果的陈化时间;随着氨水加入量的增加,SiO2颗粒的粒径增大;掺入有机添加剂N,N-二甲基甲酰胺可以提高薄膜的性能,有效抑制颗粒生长;氨水催化制备的薄膜透过率相对较高,膜层峰值在640～690nm范围内透射率达99%以上。

Porous silica film was prepared through sol-gel process and impregnation method with a precursor sol containing of tetraethoxysilane（TEOS） in base catalyst. The influence of the content of anamoni on the performance of the SiO2 sol and coating was studied in detail. Thermal stability in drying process of the SiO2 sol were studied by Netzsch thermal analyzer;the structure and morphology of these samples were characterized by SEM;the optical properties of porous silicon thin film were studied by spectrophotometer. It＇s found that the viscosity of silicon sol was impervious to the increase of the NH3/TEOS molar ratio, whereas its optimal time for coating was shortened;by increasing the content of anamonia, the size of SiO2 particles increases. Doping organic additive N, N-DMF can improve the performance of the film, effectively control the growth of particles. The SiO2 sol catalyzed by NH3 had the high transmittance, which the peak value are all above 99% between 640-690nm.