中文摘要：

采用正硅酸四乙酯为前驱体，氨水为催化剂，在溶胶过程中添加聚乙二醇（PEG），调控溶胶结构，获得具有不同性能的多孔SiO2凝胶薄膜。研究了不同PEG添加量和平均分子量对溶胶粘度、镀膜时溶胶的结构以及薄膜的表面形貌和光学性能的影响。结果表明：PEG的引入能够快速增大溶胶的粘度，促进溶胶中粒子的生长，提高颗粒之间的交联度并诱导粒子呈现出均匀的环状结构。随着PEG添加量的增加，薄膜表面的疏松程度先增加后慢慢变为致密结构，薄膜折射率在1.1~1.47之间可调，而镀膜玻璃的透过率先缓慢增加到99.32%，然后迅速降低。随着PEG平均分子量的增加，薄膜表面的大孔先逐渐增多然后变为致密结构；镀膜玻璃的透过率降低，最高为99.73%；薄膜折射率在1.14~1.38之间可调。PEG的添加量越多、平均分子量越大，对溶胶结构和薄膜性能的影响越显著。

英文摘要：

To control the structure of silica sol and obtain porous silica coatings, polyethylene glycol （PEG） was introduced intothe sol process using tetraethoxysilane as precursor and ammonia as catalyst, respectively. The effects of content and average molecular mass of PEG on the sol viscosity, particle distribution, surface morphology and optical property of the coatings were investigated. The results show that the introduction of PEG results in a rapid increase of the viscosity of sols, promotes the growth of silica particles, increases the crosslinking degree between particles, and induces the particles to present a uniform ring-like structure. With the PEG content increasing, the porosity of sol-gel silica coatings firstly increased and then decreased, the transmittance of coated glass reach to a maximum of 99.32% at the molar ratio of PEG to TEOS of 0.052, and the reflective indices can be continuously adjusted between 1.14-1.47. Besides, with the PEG average molecular mass increasing, the porosity of silica coatings also firstly increased and then decreased, the transmittance decreases and the maximum value can reach to 99.73% at the average molar mass of PEG of 200, and the refractive indices can be adjusted between 1.14-1.38.