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 documented. The silica gel acts as a porous-high-surface-area substrate for the in-situ chemical synthesis of conducting polypyrrole in aqueous media. However, the surface of such materials is silica-rich as found by XPS. In order to obtain similar hybrid particles with, instead, a polypyrrole-rich surface, we pretreated the silica gel particles with a silane coupling agent (ie aminopropyltriethoxysilane, APS) prior to polypyrrole (PPy) coating. This led to the synthesis of novel hybrid PPy-silica-APS materials which were characterized by TGA, elemental analysis. XPS, SIMS, BET and conductivity measurements. These novel hybrid particles have higher PPy loadings, exhibit a high specific surface area with a PPy-rich surface, and are three orders of magnitude more conductive than the particles prepared without APS pretreatment.