text: EQCM can be used to ideally modify polymer membranes together with other electrochemical measurements or surface characterization methods. A team has used CV, UV-Vis, IR and EQCM studied irreversible changes of some polythiophenes in the electrochemical reduction process in acetonitrile. Later on they used AFM and EQCM investigated growth of polypyrrole film in anionic surfactant micellar solution. Then combing with CV, UV-Vis, FTIR, ESR, they used EQCM to study conductivity and magnetic properties of 3,4-dimethoxy and 3,4-ethylenedioxy-terminated polypyrrole and polythiophene.