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以氨水作催化剂,采用溶胶-凝胶法制备出单分散、粒径约300～500nm的亚微SiO2粒子。研究了氨水浓度、乙醇用量、正硅酸乙酯/水的体积比及硅烷偶联剂浓度对SiO2粒子粒径、分散度及其表面结构的影响,同时还研究了SiO2胶体粒子的稳定性能和成核生长机理。结果表明:SiO2粒子粒径随氨水浓度的增加,先增大后减小,分散度增大;且随着乙醇用量的增加,粒径减小,分散度下降。硅烷偶联剂的加入使得SiO2胶体粒子表面有机成分增多,疏水性增强,其水乳液在常温下不能长久放置,且硅烷偶联剂浓度愈高,粒子间愈容易发生黏连。
Ammonia was used as catalyst to prepare submicron SiO2 particles with monodispersion and particle size of 300 ~ 500nm by sol - gel method. The effects of ammonia concentration, ethanol concentration, volume ratio of TEOS / water and the concentration of silane coupling agent on the particle size, dispersion and surface structure of SiO2 particles were studied. The stability of SiO2 colloidal particles Nucleation and growth mechanism. The results showed that with the increase of ammonia concentration, the particle size of SiO2 increased firstly and then decreased, and the dispersion degree increased. With the increase of the amount of ethanol, the particle size decreased and the dispersion degree decreased. The addition of silane coupling agent increases the organic components on the surface of SiO2 colloidal particles and enhances the hydrophobicity. The water emulsion can not be placed at normal temperature for a long time, and the higher the concentration of silane coupling agent, the more the adhesion between particles will occur.