Synthesis of composite based on submicron sized silver particles hosted on microspheres of surface-functional porous crosslinked copolymer networks

This study presents a different colloidal silver (Ag)/polymer system where Ag submicron particles are anchored onto surface-functional porous microspheres of various commercial copolymers networks, namely Amberlite (R) GT73 (resin containing thiol group) and Amberlyst (R) 15WET from Rohm and Haas Co. and Lewatit (R) VPOC1800 from Bayer Co., both containing sulfonic acid group. The Ag/microsphere composites were prepared via in situ reduction of Ag salt (AgNO3) by employing three different reductants, namely hydrazine, hydroxylamine and formaldehyde (under alkaline pH). The formation and morphology of the composite microspheres were characterized by scanning electron microscopy (SEM) equipped with backscattered electrons detector (BSE). Energy dispersive X-ray spectroscopy (EDS) coupled to SEM allowed the observation of submicron particles in the 50-500 nm size range, which chemical microanalysis of emitted X-rays revealed the presence of metal on the microspheres surface. The significance of the present report is that owing to the affinity between Ag and functional groups of the different copolymers studied on the large surface of the microspheres, it was possible to have an insight on the influence of the functional group in the Ag particles dispersion profile in the composite. Thus Ag particles were observed to be incorporated evenly into the deep pores of the beads with fine size and narrow size distribution in GT73 resin, while non-uniform coarse precipitation was observed in VPOC1800 and 15WET resins. It appears that the morphological features could be strongly influenced by the chemical composition. (c) 2006 Elsevier B.V. All rights reserved.