INVESTIGATIONS ON CONDUCTING POLYMER-FILMS WITH A FAST ELECTROCHEMICAL QUARTZ CRYSTAL MICROBALANCE

A fast electrochemical quartz crystal microbalance (EQCM) is presented, by means of which it is possible to obtain a resolution of a few nanograms within a measuring time of one millisecond. So, mass changes accompanying cyclic voltammetry (CV) of high scan rates as well as step experiments can be recorded. - The EQCM was used for the investigation of ion-exchange properties of conducting polymers, especially polypyrrole, which was electropolymerised potentiodynamically onto gold in aqueous solution. The insertion and expulsion of counterions (anions and/or cations) during the electrochemical change of the oxidation state of the film was studied. From the mass change and the accompanying current the different contributions of the ions to the exchange could be determined.