TEOS-MTES基SiO2溶胶微结构的SAXS研究

正硅酸乙酯(TEOS)为前驱体,在碱性条件下制备含有无定形SiO2颗粒的溶胶,以甲基三乙氧基硅烷(MTES)在酸性条件下获得聚甲基硅氧链,二者混合后应用同步辐射X射线进行混合溶胶的SAXS散射强度测定,计算了溶胶的平均回转半径、平均粒径、两相界面层厚度、散射体体积分数、两相间比表面积等参数,辅以光子相关光谱法(PCS)和透射电子显微镜(TEM)观测溶胶粒度,证实SiO2颗粒被MTES混合物连接成族团.实验发现所测混合溶胶样品均表现出对Porod定理的负偏离,说明溶胶中颗粒与溶剂之间存在很明显的两相间界面层.

Study of the Microstructure of TEOS-MTES Based Sol by SAXS

A basic sol containing amorphous SiO2 particles was prepared by sol gel process with TEOS ( tetraethoxysilane ) as precursor in alcohol system.A solution containing polymer of MTES ( methyltriethoxysilane ) was also prepared under acidic condition.The mixed sol was tested by the small angle X ray scattering (SAXS) at Station of Beijing Synchrotron Radiation Facility (BSRF).The average rotation radius,the average particle diameter,the percentage of scattering particles,the thickness of interface layer and the specific inner surface area between the two phases were calculated.With the assistant of photon correlation spectrum (PCS) and transmission electronic microscopy (TEM),the microstructure of TEOS MTES mixed sol was obtained in which SiO2 particles were interlinked through the polymers of MTES.By SAXS experiment,we found negative deviation from the Porod law on all the samples,which showed clearly interface layer between the two phases in mixed sol.