A study of ion transports and growth of conducting polypyrrole with electrochemical quartz crystal microbalance

Growth of polypyrrole and ion exchange processes in the polypyrrole were investigated by an electrochemical quartz crystal microbalance for various eletrolytes. The polymer was deposited potentiodynamically or potentiostatically on a gold film electrode. The mass change associated with insertion and expulsion of ions in the polymer matrix with successive potential scans at the electrode and during the growth of the polymer were monitored in situ. The observation supports that insertion of anions into polymer matrix in CH3CN occurs for anodic polarization and expulsion of the same ion for cathodic polarizaiton. However, charge compensation occurs also by cations in aqueous electrolyte even when the polymer is composed of small dopant anions. Also, it is found that growth of polymer is much faster and induction period is much shorter in H2O than in CH3CN.