Dual-Mode Behavior in Doping–Undoping of Polypyrrole with Alkanesulfonate

Polypyrrole (PPy) films incorporated with a series of 1-alkanesulfonates, RnSO3− (CnH2n+1SO3−, n=3–10), were prepared by the electrochemical polymerization of pyrrole in H2O containing sodium salt of RnSO3−. The mass transfer in the PPy matrix of the RnSO3− incorporated PPy (PPy/RnSO3−) films were investigated by electrochemical measurements. The electrochemical properties of PPy/RnSO3− were affected by the chain length of the incorporated RnSO3−. The incorporation and release of cationic species into the PPy/RnSO3− matrix during an electrochemical oxidation–reduction of PPy were observed and the contribution of cationic species during the doping-undoping process was increased with the dopant size. The PPy/RnSO3− showed a dual-mode behavior during the electrochemical doping–undoping process.