Polymer-Gold Composite Particles Via Pickering Emulsion Polymerization: Synthesis, Characterization and Application

A one-step Pickering emulsion polymerization route was successfully applied to synthesize core-shell polystyrene-gold composite particles. Interestingly, in addition to core-shell structured polystyrene-gold composite particles, we found asymmetric polystyrene-gold nanocomposite particles are also produced, where a single gold nanoparticle is attaching on each polystyrene substrate. It is found these asymmetric particles are formed via “seeded-growth” mechanism.  The core-shell and asymmetric polystyrene-gold composite particles proves to be efficient catalysts as they successfully catalyzed Rhodamine B reduction reaction. Further, PNIPAAM were successfully incorporated to produce “smart” polystyrene-PNIPAAM-gold composite particles. Without the aid of cross linker, the synthesized particles have up to 72% size decrease percentage. The polystyrene-PNIPAAM-gold asymmetric particles are found to have tunable optical properties due to thermo-responsiveness of PNIPAAM. It is found that absorption/scattering intensity could be adjusted significantly and the refractive index of substrates of the asymmetric particles influence their SPR properties. These tunable optical properties show great potential for biomedical and optical applications.