Conductive composites of polypyrrole and sulfonic-functionalized silica spheres

Colloidal silica spheres were sulfonic-functionalized by the pretreatment of a mercapto-containing silane coupling agent and further oxidation. Starting off with these functionalized silica spheres, we successfully fabricated a silica-polypyrrole (PPy) core-shell nanostructure. FT-IR and TGA were used to characterize the resulting composite. Because of the complete coating of polypyrrole, the electric conductivity of the composite was as high as 12 S/cm, three orders of magnitude higher than that of conventional silica-polypyrrole composites. The colloidal stability can be improved greatly by introducing a common steric agent poly(N-vinylpyrrolidone) (PVP) into the system. (c) 2006 Elsevier B.V. All rights reserved.