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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。
Monodisperse silica microspheres were synthesized by the method of Stober. The effects of reaction conditions on the particle size and monodispersity of the spheres were systematically studied. The microspheres were characterized by transmission electron microscopy. With the increase of ammonia concentration and tetraethyl orthosilicate, the diameter of the silica microspheres formed gradually decreased. Under the condition of high temperature, the microspheres with smaller particle size will be formed. The increase of solvent viscosity will also increase the particle size of the formed microspheres. On the other hand, adding electrolyte to the reaction system can effectively increase the size of the sphere, thus providing a simple and effective method for preparing micrometer-sized silica microspheres. The related reaction mechanism was studied. According to the change of these reaction conditions, the conditions for preparing monodisperse silica microspheres with different particle sizes were determined.