Monitoring of the electrochemical degradation of PEDOT films on gold using the bending beam method

Electrochemical and mechanical properties of thin poly(3,4-ethylenedioxythiophene) films deposited on gold have been investigated in aqueous sulfuric acid and sodium-sulfate solutions. It has been shown that at sufficiently positive electrode potentials, overoxidation of the polymer takes place. In some cases, only small changes could be observed in the shape of cyclic voltammograms taken in the stability region before and after overoxidation. In contrast to this, the impedance spectra recorded after overoxidation differed considerably from the impedance spectra of a freshly made electrode. Morphological changes of the polymer caused by overoxidation (degradation) could be detected by using the bending beam method.