Abstract
Electroactive poly(aniline) films, which are electronic conductors in their oxidized form, can be electrochemically formed on metal electrode surfaces. Above 
in acid solutions, oxidized films undergo a partially reversible transition to an insulating state. Impedance measurements have been used to characterize the electrical properties of these films under potentiostatic conditions and during potential cycling. In addition to probing their electronic conductivity, such measurements yield information regarding ionic conduction, charge capacity, and relaxation processes. The gradual loss of activity which occurs in the oxidized, insulating state is accompanied by a major loss of electronic conductivity and a lesser decrease in charge capacitance.