INDUCTANCE EFFECT IN THE AC-IMPEDANCE OF CONDUCTING POLYPYRROLE FILMS

It was found that a conducting polypyrrole (PPy) film strip with two Ag-paste electrodes exhibited an inductance in the AC impedance measurement. An equivalent circuit was proposed for an approximate analysis of experimental data. The effect of the physical dimensions on the parameters of the elements of the equivalent circuit is given. The parameters were found to be sensitive to the applied AC field strength. Although the DC conductivity of a conducting PPy film is isotropic in the film plane, the conductivity for the applied field in the thickness direction is some 4 orders of magnitude smaller and highly non-ohmic even at low fields of over 4V mm-1. The anisotropy in the thickness direction of AC impedance is also very pronounced.