Synthesis of silica-polystyrene core-shell nanoparticles via surface thiol-lactam initiated radical polymerization

This paper reports the synthesis of structurally well-defined silica-polystyrene (SiO₂@PS) hybrid nanoparticles using a thiol-lactam-initiated, radical-polymerization technique. The surface of silica particles, 80 nm in size, were functionalized with (3-mercaptopropyl) trimethoxysilane and used as seeds in the polymerization of styrene in the presence of butyrolactam. ¹H nuclear magnetic resonance and X-ray photoelectron spectroscopy showed that the thiol groups on the SiO₂ surface could initiate polymerization with the aid of butyrolactam. Transmission electron microscopy showed that the hybrid particles had uniform core-shell morphologies. The molecular weight of grafted PS increased with increasing polymerization time.