Modulating the catalytic activity of Au/micelles by tunable hydrophilic channels

Polymeric micelles with a polystyrene core, poly(acrylic acid)/poly(4-vinyl pyridine) (PAA/P4VP) complex shell and poly(ethylene glycol) & poly(N-isopropylacrylamide) (PEG & PNIPAM) mixed corona were synthesized and used as the supporter for the gold nanoparticles (GNs). It was concluded from the result of (1)H NMR characterization that hydrophilic channels formed around PEG chains when PNIPAM collapsed above its lower critical solution temperature. The density of the channels in the corona can be tuned by changing the weight ratios of PEG chains to PNIPAM chains. The GNs were set in the PAA/P4VP complex layer and the catalytic activity of the GNs can be modulated by the channels. The catalytic activity increased with increasing the density of the channels in the corona. Meanwhile, the whole Au/micelle nanoparticles were stabilized by the extended PEG chains.