Gold-Loaded Polymeric Micelles with TemperatureModulated Catalytic Activity

Four-armed amphiphilic block copolymers, polystyrene-b-poly（N-isopropylacrylamide）（PS-bPNIPAM）4, were synthesized by atom transfer radical polymerization（ATRP）.（PS-b-PNIPAM）4 self-assembled into micelles with PS block as core and thermoresponsive PNIPAM block as corona. The gold nanoparticles（Au NPs） with average diameter about 5.8 nm were immobilized on the surfaces of the micelles by the reduction of the corresponding ions. The micelle-supported gold nanoparticles（Au-micelles） were applied to catalyze the reduction of p-nitrophenol. Moreover, the activity of the Au-micelle catalyst could be modulated by the temperature and the Au-micelles could be easily recovered by changing the temperature and recycled four times with high catalytic activity.