单分散二氧化硅球形颗粒的制备与形成机理

在醇水混合溶剂中以氨作催化剂，正硅酸乙酯为硅源，通过溶胶—凝胶工艺制 备单分散二氧化硅球形颗粒，通过透视电镜进行研究各种反应条件如溶剂类型、氨 和水的浓度、水解温度等对二氧化硅的颗粒大小和形貌的影响．结果显示：以甲醇 和乙醇为溶剂可以形成单分散的二氧化硅球形颗粒，以丙醇和丁醇为溶剂，二氧化 硅球形颗粒容易聚集；在其它条件不变的情况下，球形颗粒的粒径随水和硅源的浓 度增加而增大；而且水解温度的升高，生成的颗粒粒径也逐渐增大，仔细研究和讨 论了二氧化硅颗粒在不同反应条件下的形成机理．

Preparation and Formation Mechanisms of Monodispersed Silicon Dioxide Spherical Particles

Monodispersed silicon dioxide spherical particles have been prepared by hydrolysis of tetraethoxy silane (TEOS) in alcohol water mixed solvents and using ammonia as a catalyst. Effects of the type of solvents, the amount of water, the concentration of ammonia and temperature of hydrolysis etc . on the particle sizes and morphology of SiO 2 were investigated by transmission electron microscopy (TEM). The results show that the monodispersed silicon dioxide spherical particles could be obtained in methanol and ethanol solvent, while agglomerated silicon dioxide particles were formed in n propanol and n butanol solvent. When the concentration of water and TEOS is increased or the temperature of hydrolysis raised, the particle sizes increase. The formation mechanisms of the resultant SiO 2 particles under different reaction conditions were carefully investigated and discussed.