Core–Shell and Asymmetric Polystyrene–Gold\nComposite Particles via One-Step Pickering Emulsion Polymerization

Abstract

Core–shell structured polystyrene–gold\ncomposite particles are synthesized from one-step Pickering emulsion\npolymerization. The surface coverage of the core–shell composite\nparticles is improved with increasing gold nanoparticle (AuNP) hydrophobicity\nand concentration. At high surface coverage, the AuNPs exhibit an\nordered hexagonal pattern, likely due to electrostatic repulsion during\nthe emulsion polymerization process. In addition to core–shell\nstructured polystyrene–gold composite particles, an intriguing\nobservation is that at low AuNP concentrations, asymmetric polystyrene–gold\nnanocomposite particles are simultaneously formed, where a single\ngold nanoparticle is attached onto each polystyrene particle. It is\nfound that these asymmetric particles are formed via a “seeded-growth”\nmechanism. The core–shell and asymmetric polystyrene–gold\ncomposite particles prove to be efficient catalysts as they successfully\ncatalyze the Rhodamine B reduction reaction with stable performance\nand show high recyclability as catalysts.