Abstract: A new composite of Au nanoparticles (AuNPs) adsorbed on thermoresponsive poly(N-isopropyl acrylamide) (PNIPAM) microgels that combines the thermoresponsive behavior of PNIPAM microgels with the optical properties of Au nanoparticles is reported. The LSPR (localized surface plasmon resonance) of the AuNPs could be changed by adjusting the temperature of the thermoresponsive PNIPAMmicrogels. An increase in temperature led to a red shift of the LSPR of the AuNPs and this change was found to be fully reversible. Optical properties of AuNPs were used to monitor the thermoresponsive behavior of PNIPAM microgels. The morphology, optical properties, and average particle size of AuNPs/PNIPAM particles were characterized by transmission electron microscopy (TEM), UV-Vis spectroscopy and dynamic light scattering.

Key words: Au nanoparticles, Poly (N-isopropyl acrylomide), Thermoresponsive microgels, Localized surface plasmon resonance