The electrochemical quartz crystal microbalance has been employed to investigate the electropolymerization of pyrrole in a variety of aqueous electrolytes. In contrast to the generally accepted cation–radical coupling process for the electropolymerization of pyrrole, an electrochemically initiated chain polymerization, featuring a high polymerization rate and involving little charge transport, was found under specific conditions in the presence of ClO−4, BF−4, and PF−6 electrolytes. The more typical cation‐radical coupling mechanism, characterized by a constant polymerization charge to mass deposited ratio, is observed in the presence of Cl−, NO−3, dodecyl sulfate, copper phthalocyanine tetrasulfonate, β‐cyclodextrin tetradecasulfate, and poly(styrene sulfonate). Electrochemical characterizations of polypyrrole films prepared in aqueous ClO−4 electrolytes reveal that the polymer formed via chain polymerization exhibits the ability to transport both cations and anions during electrochemical switching between redox states, while the polymer synthesized through cation‐radical coupling is only capable of transporting a single ionic species.

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A combination of electrochemical and microgravimetric techniques, utilizing the electrochemical quartz crystal microbalance (EQCM), has been employed to study the ion transport behavior of polypyrrole films, prepared with a variety of electrolytes, during redox switching. Systems investigated include poly(pyrrole chloride), poly(pyrrole dodecylsulfate), poly{pyrrole‐co‐[3‐(pyrrol‐1‐y1)propanesulfonate]}, and polypyrrole/Nafion composites. It has been demonstrated that controlled ion transport properties of polypyrrole can be achieved by incorporating properly selected dopant anions into the polypyrrole film during electrosynthesis.

A water-soluble, self-doped, electroactive polymer, poly [3,6-(carbaz-9-yl)propanesulfonate] (PCPS), has been prepared for the first time. Electrochemical ~.,alyses show that this polymer has two separate oxidation states involving interactions of the polymer backbone with the covalently bound, self-doping ions and counterions from electrolyte, indicating that the polymer has the ability to act as a potential-dependent charge-controllable membrane with both cation-exchange and anion-exchange properties. We have used the quartz crystal microbalance technique to investigate these two processes, to verify the self-doping mechanisms exhibited by PCPS, and detail the charge/mass transport relationships in this polymer.

The fabrication and electrochemical characterization of a variety of self-supported, thermoreversible organic electrolyte gels prepared using 1,3 : 2,4-dibenzylidene sorbitol (DBS) as a gelling agent are reported. Impedance analysis and cyclic voltammetry were used to examine these gel systems, which exhibit ionic conductivities similar to corresponding liquid electrolyte solutions.