由硅溶胶生长单分散颗粒的研究

针对现行单分散二氧化硅颗粒制备方法的粒径预见性差、步骤繁琐、收率低等问题，研究了一种用硅溶胶作为种子，在氨、水和乙醇的混合溶液中通过水解正硅酸乙酯（ＴＥＯＳ）生长出单分散颗粒的简便方法。该方法仅在初始的悬浮液中滴加ＴＥＯＳ即可使种子正常生长，无须补充氨水以修正体系浓度的变化。最终的分散相浓度可达１０％（质量分数）。可选择生长的粒径范围在１微米以内并可精确控制。所得颗粒粒径分布偏差于Ｓｔｏｂｅｒ方法

Preparation of Monodisperse Silica Spheres by Growth of Silica Sol Particles

A new process for preparing monodisperse silica spheres was developed to improve the accuracy of predictable diameter of particle and simplify the experimental procedure. It involves growth of commercial silica sol particle in an original mixture solution of ammonia, water and ethanol with continuous introduction of tetraethoxysilane and without compensation for the decrement of water and ammonia concentrations during the formation of monodisperse spheres. The final concentration of silica can reach about 10% by weight in the reaction mixture. The desired diameter of the particles up to 1μm at choice can be controlled accurately. The deviation of particle size distribution was less than that of the Stober spheres. The influence of the number density of reactants, temperature and the flow rate of tetraethoexy silane on the deviation of the size distribution of final particles was investigated.