Doping competition of anions during the electropolymerization of pyrrole in aqueous solutions

The doping competition of anions in the electropolymerization of pyrrole was studied in aqueous solutions containing two kinds of anions with the same concentration of 0.1 mol dm-3. The composition analysis of the polypyrrole (PPy) films prepared shows that the doping amount of p-toluene sulfonate (TsO-) prevails over that of perchlorate, chloride and nitrate anions. The conductivity of the PPy film is close to the higher value of the two PPy films doped with a single anion. When polymerization is performed in the solution containing TsO- and NO3-, TsO-is mainly doped at Structure I, while NO3- is mainly at Structure II of the PPy film.