Design of polymer particles maintaining dispersion stability for the synthesis of hollow silica particles through sol-gel reaction on polymer surfaces

Abstract

To synthesize polystyrene-silica core-shell particles and silica hollow particles, soap-free emulsion polymerization was carried out using styrene and N-vinylacetamide (NVA), and the Stöber method using tetraethyl orthosilicate (TEOS) was performed on the polymer particle surfaces. Here, NVA acts as a stabilizer for the polymer colloids, maintaining dispersion stability by synthesizing hydration layers even when the electrostatic adsorption of TEOS had occurred, and as a catalyst for the sol-gel reaction. NVA was polymerized by the cationic initiator located on the surface of the polystyrene particles to maintain dispersion stability by a steric effect. Therefore, the sol-gel reactions proceeded more efficiently on the surface of polymer particles, facilitated by the much larger surface area. Finally, the polymer core was removed by heating to prepare highly monodisperse silica hollow particles.