Optimization of the electrical conductivity of polypyrrole films electrogenerated on aluminium electrodes

Polypyrrole films were electrogenerated by square-wave potentials, as homogeneous, adherent smooth layers, from NtBu p-CH3C6H4SO3 in acetonitrile solutions on aluminium electrodes. The conductivities of the obtained films range from 10 to 350 S cm−1 as a function of electrical and chemical variables of synthesis. The observed effects of the preparation conditions on the film conductivity are explained in terms of the polymerization mechanism, in order to prepare high-quality films. The evolution of the conductivity of these polymers as a function of their oxidation states has also been investigated. The conductivity changes from 10−6 to 3×102 S cm−1 when the polymer passes from a neutral state to an oxidized state, by variation of the electrochemical potential from −800 to 200 mV (versus SCE).