Quartz Crystal Microbalance Study: Ionic Motion Across Conducting Polymers

In situ monitoring of mass change was performed during electrochemical growth and redox cycling of a conducting polymer(polypyrrole) on a quartz crystal microbalance. For the polypyrrole films grown with large polymeric anions(poly(4-styrenesulfonate) and polyvinylsulfonate), mostly cations and solvent molecules were inserted and removedto compensate charge in polypyrrole. The films formed with medium-sized anions (tosylate) showed both apparent anion and cation motion during the redox process. The films prepared in the presence of small anions (C1O4-and BF4) showed mostly anion motion, but apparent cation motion also became significant for higher oxidation and/or reduction state.