Surface infusion of gold nanoparticles into processed thermoplastics

Stable dispersions of gold (Au0) 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 HAuCl4 in a ternary solvent mixture held well below the melt‐processing temperature of the plastic. Rapid infusion of plasticizing solvents and HAuCl4 is achieved for several thermoplastic polyurethane elastomers and an acrylic‐pyrrolidinone copolymer. A second infusion of triethylamine, a reducing agent, produces Au0 nanoparticles in a surface layer of (10–30 μm) depth. Precipitation of Au0 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 Au0 particle size distribution can be manipulated by changing processing conditions that affect the formation of aggregates, such as the concentrations of HAuCl4 and plasticizers. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers