Synthesis and characterization of gold-based nanoscopic additives for polymers

A new chemical route for the synthesis of alkanethiol-derivatized gold clusters of controlled size to be used for polymer functionalization has been developed. Gold clusterswere prepared by reduction of tetrachloroauric acid with ethylene glycol in the presence of poly(N-vinyl pyrrolidone) (PVP) as stabilizer. PVP-protected gold clusters were separated from the reactive mixture by floccuation with acetone; they were then dissolved in a dodecanethiol/ethanol solution to produce thiol derivatized Au clusters. Passivated clusters were dispersed in polystyrene/chloroform solution and high-transparent purple colored nanocomposite films were obtained by solution casting. This preparative scheme allows production of high-quality polymer based optical filters with complete control over the absorption properties.