MICRO-RHEOLOGY CHANGES OF NAFION(R) FILMS WITH ELECTROCHEMICAL MASS-TRANSPORT IN HYDROQUINONE SOLUTIONS AND IN SITU MEASUREMENT USING A QUARTZ CRYSTAL ANALYZER

This paper shows that the electrochemical mass transport in film-coated electrodes involves the rheology change of the films and that these changes can be detected by measuring the resonant frequency and resonant resistance of a coated quartz crystal. We used a Nafion(R)-coated quartz crystal and measured the cyclic voltammograms in hydroquinone solution. The changes of the resonant frequency and resonant resistance showed that mass transport and viscoelastic changes had occurred in the Nafion films. The diagrammed resonant frequency and resonant resistance changes suggested that the Na ion de-doping from the films decreased the film mass and increased the film rigidity in the first oxidation process, the benzoquinone accumulation and anion doping increased the film mass in the following oxidation process, while the Na ion re-doped in the first reduction process, and benzoquinone was reduced from the films in the final reduction process. Study of the charge expended from the reaction suggested the participation of anion or water transport.