SLOW RELAXATION IN CONDUCTING POLYMERS - INFLUENCE OF THE WAIT POTENTIAL

It has been shown that the kinetics of the electrochemical doping of a conducting polymer depends on the time spent in the neutral state, t(w), In particular, for increasing t(w), the oxidation peak current upon potential scanning is higher and higher, and is shifted according to a logarithmic law : V(r) = V(o) + a log t(w). Further investigations of this effect are presented. In particular, the influence of the potential imposed during the wait time V(w), is investigated in the case of a polyaniline film in acidic aqueous solution. It is shown that the relaxation effect can be observed also at potentials corresponding to a significant doping level, the film being conducting. Charging of the film during waiting in this range of potential is very slow (logarithmic law). It is predicted from the data that reaching equilibrium would require about one year.