Analytical Sciences

Electrochemical and Spectroelectrochemical Characterization of Some Polypyrrole/Anthraquinone Sulfonate Films

S. M. AHMED, Tsutomu NAGAOKA * and Kotaro OGRA

Department of Applied Chemistry, Faculty of Engineering, Yamaguchi University, Tokiwadai, Ube 755, Japan

We have fabricated composite films of polypyrrole/quinone sulfonate via electropolymerization. The FTIR investigation indicated the incorporation of quinone sulfonate in the polypyrrole (PPy) film to compensate for a positive charge in the polymer chain. Further, the elemental analysis of PPy/9,10-anthraquinone-2-sulfonate (AQS - ) showed that 0.29 of the sulfonate was incorporated per pyrrole unit. Cyclic voltammetric results in dimethylsulfoxide and dimethylformamide solutions showed that the two 1-electron transfer steps could be assigned to the formation of radical dianion (AQS 2-. ) and trianion (AQS 3- ). The positive shift of the first cathodic peak for the incorporated AQS - indicated a strong interaction between the dianion and the cationic sites of the polymer. The PPy/AQS - film worked as a cation-exchanger at electrode potentials below about -0.3 V vs. Ag/AgCl (saturated KCl) because of the creation of the anionic sites of the reduced quinone. (Keywords: Polypyrrole, anthraquinone sulfonate sodium salt, cation exchange property)

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