单分散二氧化硅微球的制备与表征

SYNTHESIS AND CHARACTERIZATION OF MONODISPERSE SILICA PARTICLES

通过Stober法合成了单分散的二氧化硅微球,系统地研究了反应条件对成球粒径及单分散性的影响,通过透射电子显微镜对其进行了表征。随着氨水和正硅酸乙酯浓度的提高,生成的二氧化硅微球的粒径逐渐减小。而温度升高的条件下则会形成粒径较小的微球,溶剂粘度的升高也会增大形成的微球的粒径。另一方面,向反应体系中加入电解质可以有效地增大球的粒径,从而为制备微米级的二氧化硅微球提供了一种简单有效的方法。研究了相关的反应机理,根据这些反应条件的变化可以确定制备不同粒径单分散二氧化硅微球的条件。

Stober method was used to prepare monodispersed silica particles,the particles were obtained by hydrolysis and condensation of tetraethyl orthosilicate（TEOS） in alcohol medium with ammonia as catalyst.Effects of the reaction parameters on the diameter and particle size distribution of silica nanoparticles were discussed in the one-factor-at-a-time method.The particles were characterized by TEM.The particle size increased with the increment of ammonia and TEOS while decreased with higher temperature.Particles could be obtained in methanol,alcohol and n-propanol,and the particles were smaller with the rise in the value of the solvent＇s viscosity coefficient.Addition of electrolytes can greatly increase the particle size and the relevant mechanisms of formation under different conditions were discussed.