Electrochemical studies on attachment of new functions to electrical conducting polymers

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Electrochemical oxidation of pyrrole has been undertaken in aqueous suspension of metal oxide. Polypyrrole films containing the oxide particles can be prepared, if metal oxide having the isoelectric point (iep) smaller than pH 4.5 is suspended in aqueous pyrrole solution. Polypyrrole films containing TiO_2 particles (iep = 6.0 - 6-7) can be prepared by electrolysis of the oxide-suspended pyrrole solution in the presence of a small amount of electrolyte anion such as SO^2-_ and 1^- which specifically adsorb on the TiO_2 particles surface in the deposition baths. The polypyrrole files containing TiO_2 and WO_3 exhibited photosensitivities due to the incorporated oxide particles, and the file containing WO_3 showed electrochromic properties due to both polypyrrole and WO_3. Simultaneous immobilization of glucose oxidase and electron mediators such as ferrocenecarboxylate and hydroquinonesulfonate anions in polypyrrole films has been accomplished by electrooxidation of pyrrole solution in … More presence of glucose oxidase and the electron mediator. The resulting polypyrrole film serves as an amperometric glucose sensors in a wide concentration range without use of any mediator dissolved in the solution. The preparation of polyaniline films incorporated with cationic methylene blue has been accomplished by electrooxidation of aniline in the presence of dissolved Naflon and methylene blue. The resulting films showed electrochemical responses of both polyaniline and methylene blue and electrochromic properties due to the incorporated methylene blue. The electrical conductivity of polypyrrole films doped with several kinds of carboxylate anions decreased with an increase in the basicity of the dopant anions. The decrease in the conductivity can be quantitatively interpreted in terms of association of positive charges in polypyrrole and dopant anions. The conductivity of polypyrrole doped with monoanions of dicarboxylic acids and phenol sulfonate ions is decreased by immersing the film in such aqueous solutions as to cause dissociation of monoanions into dianions and hydroxyl groups into phenoxide ions, and the magnitude of the conductivity change was dependent on the degree of the dissociation of the dopants. Less