Electrochemical preparation and characterization of hybrid films composed of Prussian blue type metal hexacyanoferrate and conducting polymer

We propose novel composite (hybrid) organic/inorganic systems that can be fabricated as thin and moderately thick (pin level) films on electrode surfaces. During electrodeposition by potential cycling alternate layers of polyanilne and metal hexacyanoferrate are produced. Polyaniline can serve as a robust, conductive, matrix for such polynuclear mixed-valence inorganic redox centers as nickel(II)hexacyanoferrate(III,II). Due to the existence of electrostatic attraction between the negatively charged metal hexacyanoferrate and the positively charge polyaniline (partially oxidized), the composite material cannot be considered as a simple mixture of nickel hexacyanoferrate and the conducting polymer. It comes from atomic force microscopic studies that the morphology of the composite film is granular, but its structure is fairly dense. The fact, that the formal potential of nickel hexacyanoferrate redox process lies in the potential range where polyaniline is conductive, allows the system to operate reversibly and reproducibly in acid electrolytes containing potassium cations. The whole concept may lead to the fabrication of composite (hybrid) films that are capable of effective accumulation of charge and show high current densities at electrochemical interfaces. (C) 2001 Elsevier Science Ltd. All rights reserved.