Electrochemical preparation and characterization of conducting copolymer/silica composite

A composite based on organic copolymer and inorganic oxide, polyaniline/poly o‐toluidine/silica (PANI/POT/SiO₂), has been synthesized successfully by a simple electrochemical method. The composite film was found to be deposited on a Pt substrate by sweeping the potential between ?0.2 and +1.0 V versus a saturated calomel electrode with a scan rate of 100 mV/s. The polymeric composite film thus obtained was characterized by scanning electron microscopy, infrared spectroscopy, conductance measurement, and cyclic voltammetry techniques. Incorporation of silica in the copolymer results a clear difference in surface morphology compared with the bulk homo‐ and copolymers. Further evidence of silica in the composite was achieved by infrared spectral analysis. Indeed, a chemical analysis of the composite matrix showed a content of as high as 25% SiO₂ in the composite thus prepared. Based on the results of cyclic voltammetric analysis, the composite electrode as prepared was found to show good electrochemical stability even at high positive potentials. It also exhibited excellent electroactivity even after incorporation of silica in the matrix. The electroactive composite film was thus examined as electrode modifier to study the redox behavior of ferrous/ferric (Fe²⁺/Fe³⁺) and hydroquinone/benzoquinone (H₂Q/Q) couples. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008