STRUCTURE OF POLY(VINYLPYRROLIDONE)-SILICA HYBRID

This paper is concerned with the solid structure of a new group of transparent glass materials which consist of an organic polymer and a metal oxide, namely a combination of poly(vinylpyrrolidone) and dry silica gel. The structure was analyzed by Atomic Force Microscopy (AFM), BET analysis method, and CP MAS C-13-NMR. BET measurement showed that the hybrid material had a quite dense structure which was much less porous than the reference dry silica gel prepared by the conventional sol-gel process. AFM analysis gave the same conclusion, i.e., it showed a granular structure of silica of about 1 nm size. Silica and PVP domains did not show any considerable aggregation. The transparent, homogeneous, and dense structure was attributed to the hydrogen-bond formation between PVP(carbonyl group) and silanol, as demonstrated by CP MAS C-13-NMR spectroscopy.