The potential dependence of electrical conductivity and chemical charge storage of poly(pyrrole) films on electrodes

The electrical conductivity of solvent and electrolyte-wetted poly(pyrrole) films is measured, both statically and dynamically, as a function of the potential applied to an electrode in contact with the film. The applied potential determines the film cxidation state. Poly(pyrrole) electrical conductivity is ohmic and indeendent of potential from 0 to +0.4V vs. SSCE, and decreases and becomes less ohmic at more negative potentials. Measurements of the chemically reactive charge stored in poly(pyrrole) as a function of potential were combined with the electrical conductivity results to yield a profile of electrical conductivity vs. average darge per monamer site in the polymer. Electrical conductivity is independent of monomer charge above about 0.15 holes/monomer unit