Multipetal-Structured and Dumbbell-Structured Gold-Polymer Composite Particles with Self-Modulated Catalytic Activity

A simple synthesis route for gold-polymer composite particles with controlled structure (multipetal structure and dumbbell structure) is developed. It is intriguing to observe that by controlling the reaction time and size of gold nanoparticles (AuNPs), tetrapetal-, tripetal-, and dumbbell-structured gold-polystyrene composite are obtained via seeded polymerization. The average number of petals on a single AuNP increases with the AuNP diameter. These particles show potential applications as building blocks for advanced ordered and hierarchical supracolloidal materials. Further, with the incorporation of poly(N-isopropylacrylamide) (PNIPAm), "smart" thermoresponsive dumbbell-structured gold-PNIPAm/polystyrene composite particles are formed. Significant size variation is validated for particles with 83 and 91 wt % PNIPAm content around lower critical solution temperature (LCST), which results in self-modulated catalytic activity.