Abstract:

Double-hydrophilic block polymer poly(ethylene oxide)-b-poly(N-isopropylacrylamide)(PEO-b-PNIPAM) was synthesized by reversible addition-fragmentation chain transfer polymerization using PEO based macro RAFT(reversible addition-fragmentation chain transfer) agent, and the block polymer was further grafted to the surface of gold nanoparticles by "grafting to" approach. The structure and temperature responsive behavior of obtained hydride gold nanoparticles were characterized by transmission electron microscopy (TEM), UV-Vis transmission, energy dispersed X-ray spectrometer and dynamic light scattering(DLS). The results show that core/shell gold nanoparticles were prepared. The average hydrodynamic radius(R_h) of core/shell gold nanoparticles slightly decreased with the temperature increasing. And there is no aggregation between core/shell gold nanoparticles during heating process due to the inhibition effects of PEO corona.

Key words: Reversible addition-fragmentation chain transfer polymerization, Ligand exchange, Core/shell gold nanoparticles, Temperature responsive behavior