Preparation of spherical silica particles by Stöber process with high concentration of tetra-ethyl-orthosilicate

In this paper, Stöber process with high concentration of tetra-ethyl-orthosilicate (TEOS) up to 1.24 M is used to prepare monodisperse and uniform-size silica particles. The reactions are carried out at [TEOS] = 0.22–1.24 M, low concentrations of ammonia ([NH3] = 0.81[TEOS]), and [H2O] = 6.25[TEOS] in isopropanol. The solids content in the resulting suspension achieves a maximum value of 7.45% at 1.24 M TEOS. Various-sized particles in the range of 30–1000 nm are synthesized. The influences of TEOS, NH3, and H2O on the size and size distribution of the particles are discussed. A modified monomer addition model combined with aggregation model is proposed to analyze the formation mechanism of silica particles.

Graphical abstractSilica particles in the range of 920–940 nm are obtained for 1.24 M TEOS at 5 °C, which results in 7.45% solid content in the suspension.Figure optionsDownload full-size imageDownload high-quality image (58 K)Download as PowerPoint slide