Preparation of silica-coated polystyrene hybrid spherical colloids

A novel preparation method for stable PS/SiO2 core-shell hybrid colloid was proposed. In this process, a positively charged PS colloid was first synthesized via surfactant-free emulsion polymerization of styrene by using a cationic initiator, and the hydrolysis and condensation of tetraethoxysilane (TEOS) was then carried out in acidic aqueous ethanol medium in the presence of PS colloids. Silica layer was deposited onto the surface of PS particle via electrostatic interaction between positively charged PS colloids and negatively charged silica. No surface treatment and centrifugation/redispersion cycle process were needed. TEM, SEM, and zeta potential measurements indicated that silica layer was successfully coated onto the surfaces of PS colloids.