Growth of SiO2 microparticles by using modified Stober method: Effect of ammonia solution concentration and TEOS concentration

Abstract

The unique structural features and suitability of the SiO2 micro particles in different application areas have mobilized a worldwide interest in the last few decades. In this report a classical method known as the Stober method has been used to synthesize silica micro spheres. These microparticles have been synthesized by the reaction of tetraethyl orthosilicate (Si(OC2H5)4, TEOS) (silica precursor) with water in an alcoholic medium (e.g. ethanol) in the presence of KCl electrolyte and ammonia as a catalyst. It has been observed that the size of the microparticles closely depends on the amount of the TEOS and ammonia. A decrease in the size of micro particles from 2.1 micrometer to 1.7 micrometer has been confirmed as the amount of TEOS increases from 3.5 ml to 6.4 ml respectively. In similar way a decrease in the diameter of the micro particles from 2.1 micrometer to 1.7 micrometer has been observed with increase in the ammonia content from 3 ml to 9 ml.