Surface infusion of gold nanoparticles into processed thermoplastics

Stable dispersions of gold (Au 0 ) nanoparticles are produced in a few commercially important thermoplastics using a novel surface infusion technique. The thermoplastic article is immersed in a dilute solution of HAuCl 4 in a ternary solvent mixture held well below the melt‐processing temperature of the plastic. Rapid infusion of plasticizing solvents and HAuCl 4 is achieved for several thermoplastic polyurethane elastomers and an acrylic‐pyrrolidinone copolymer. A second infusion of triethylamine, a reducing agent, produces Au 0 nanoparticles in a surface layer of (10–30 μm) depth. Precipitation of Au 0 nanoparticles is arrested by the high viscosity of the plasticized polymer matrix, resulting in a stable dispersion, but formation of aggregates is possible in some plastics. The Au 0 particle size distribution can be manipulated by changing processing conditions that affect the formation of aggregates, such as the concentrations of HAuCl 4 and plasticizers. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers