Effect of prolonged electrode potential cycling on the charge transport parameters of poly(o-aminophenol) films. A study employing rotating disc electrode voltammetry and surface resistance

Abstract

The aim of this work was to study the effect of prolonged potentiodynamic cycling (PPC) on the conducting properties of poly(o-aminophenol) (POAP) film electrodes. Cyclic Voltammetry (CV), Rotating Disc Electrode Voltammetry (RDEV) and Surface Resistance (SR) were employed in this study. The attenuation of the voltammetric response of the polymer with the increase in the number of oxidation–reduction cycles allowed one to define a degree of deactivation. RDEV was employed to obtain the dependence of the electron diffusion coefficient on the degree of deactivation of the polymer. The slower electron transport with the increase in the degree of deactivation was attributed to the increase of the electron hopping distance between redox sites. The attenuation of the relative resistance changes (ΔR/R) of a gold film coated with a POAP film as the degree of deactivation increases was also associated to changes in the redox site configuration at the gold/POAP interface after PPC. POAP films maintain their conducting properties almost unaltered for about 500 potential cycles at a scan rate of 0.010Vs−1. However, a loss of conductivity was observed as the number of potential cycles was extended beyond 500.