DC-RESISTOMETRIC STABILITY STUDIES ON A CONDUCTING POLYMER (POLYPYRROLE) FILM IN AN AQUEOUS-SOLUTION

A DC-resistometric method was used to study the stability of a chloride doped polypyrrole film. The film was found to maintain its conducting properties longer when stored in the reduced state or disconnected from the potentiostat. The half life of the reciprocal of the resistance for a film with an initial value of 5.0 mS was 5.0 hours at -600mV (reduced state) vs. an Ag/AgCl-reference electrode and 6.8 hours when disconnected. At + 600 mV (oxidised state) the half life was 1.0 hour. Furthermore it was shown that slower deactivation was associated with thicker films. It was observed that the decay in the reciprocal of the resistance was found to be an exponential function of the storage time during a 5 hours time period.