Controlling the morphology of gold nanoparticles synthesized photochemically in a polymer matrix through photonic parameters

A facile method for the preparation of gold nanoparticles (AuNPs) with various morphologies, including triangles, cubes and nanospheres into a urethane methacrylate polymer matrix, has been developed. The hybrid nanocomposites have been obtained by photoreduction of a gold precursor in the presence of a 30 wt% urethane methacrylate containing quaternary ammonium structure and 70 wt% functional monomer, carboxyl oligo-urethane dimethacrylate. The final materials contain gold nanoparticles with a morphology dependant on the reaction conditions. The influence of photonic and chemical parameters on the shape of the nanoparticles has been examined. Specific interactions between the macromolecular network and the nascent particles play an important role insofar as they control the access of metal atoms to the different crystalline planes of the growing nanoparticles, which is necessary to obtain anisotropic objects. A common mechanism for the formation of the various types of AuNPs is proposed. Coupling the intrinsic characteristics of metal nanoparticles with those of the copolymer substrate could result in materials with innovative properties. (paper)