Growth of Monodisperse Silver Nanoparticles in Polymer Matrix by Spray Pyrolysis.

Silver nanoparticles were simply prepared by spray pyrolysis of aqueous solutions of AgNO3, and dextran or Poly (vinylalcohol) (PVA) without any reducing agent. Monodisperse particles well-organized in polymer matrix were obtained above a certain critical ratio of polymer to silver nitrate, usually around 1, and below decomposition temperatures of the polymer. Otherwise, the silver particles grew polydisperse due to the imperfect confinement of the polymer. Their shapes varied from facetted with dextran to spherical with PVA, depending on the interaction of silver and the polymer. The confinement increased and thus the critical ratio decreased by increasing the molecular weight of the polymer and replacing PVA by dextran. Above the ratio, the particles got smaller with the concentration of dextran, while their size did not vary in PVA due to its configuration. [ABSTRACT FROM AUTHOR]