The role of a silane coupling agent in the preparation of novel hybrid polypyrrole-silica particles.

The preparation of hybrid polypyrrole-silica gel particles is well document ed. The. silica: gel acts as a porous-high-surface-area substrate for the i n-Situ chemical synthesis of conducting polypyrrole in aqueous media. Howev er, the surface of such materials is silica-rich as found by XPS. In order to obtain similar hybrid particles with, instead, a polypyrrole-rich surfac e, we pretreated the silica gel particles with a silane coupling agent tie aminopropyltriethoxysilane, (APS) prior to polypyrrole (PPy) coating. This led to the synthesis of novel hybrid PPy-silica-APS materials which were ch aracterized by TGA, elemental analysis, XPS, SIMS, BET and conductivity mea surements. These novel hybrid particles have higher PPy loadings, exhibit a high specific surface area with a PPy-rich surface, and are three orders o f magnitude more conductive than the particles prepared without APS pretrea tment.