Synthesis and characterization of gold-based mesoscopic additives for polymers

A method for the controlled synthesis of alkanethiol-derivatized gold clusters to be used as fillers for polymeric nanocomposites has been developed. Gold clusters embedded in poly(N-vinyl pyrrolidone) (PVP) were obtained by reduction of AuCl4- with ethylene glycol in the presence of PVP as a stabilizer. The gold/PVP system was separated from the reactive mixture by flocculation with acetone, and this material was treated with a dodecanethiol/ethanol solution to produce thiol-derivatized gold clusters. Then, the clusters were dispersed in polystyrene/chloroform solutions and highly transparent purple-colored nanocomposite films were obtained by solution casting. This preparative scheme allows one to obtain high-purity nanocomposites, with complete control over the filler percentage and size