Electrochemical Impedance of Polypyrrole Films under Different Conditions

We electropolymerized polypyrrole (PPy) films doped with para-toluene sulfonate (pTS-) and dodecyl sulfonate (DS-) by a galvanostatic method.The influence of potential and overpotential process on the electrochemical properties of the PPy films in NaCl aqueous solution were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS).In addition,the influence of insertion with or without ions on the PPy films was also studied by the EIS of PPy inserted with or without Na+ or Cl-ions in specially prepared aqueous solutions.Results showed that the ionic conductivity and the capacitance of the PPy films increased after the first CV and the electronic conductivity of the PPy/pTS increased after the insertion of Cl-ions.However,PPy films inserted with or without Na+ ion showed little difference in the EIS of the PPy films.Furthermore,the ion conductivity was affected by a change in the microstructure of the PPy films with or without ions which was also apparent in the EIS.