Electrode kinetics of poly ( o-aminophenol) film prepared by electro-oxidative polymerization of o-aminophenol and its electrochromic properties

Abstract

A kinetic examination of the charge-transport process ( ie, (i) heterogeneous electron-transfer process at electrode—film interfaces and (ii) homogeneous charge-transport process within films) at poly( o-aminophenol (PAP) film-coated electrodes, which were prepared in situ by electro-oxidative polymerization of o-aminophenol in an acidic solution, has been conducted by potential-step chronoamperometry (and chronocoulometry) and normal pulse voltammetry. The kinetic parameters characterizing processes (i) and (ii) ( ie, standard rate constant ( k°) and transfer coefficient (α) for process (i) and apparent diffusion coefficient ( D app) for process (ii)) were estimated: D app (for anodic and cathodic processes) = (1 ∼ 6) × 10 −10 cm 2 s −1, k° = 1.1 × 10 −4 cm s −1, α (for anodic process) = 0.75 and α (for cathodic process) = 0.21. They were compared with the data reported previously for the electropolymerized poly( o-phenylenediamine) which is a ladder-structured polymer similar to PAP. In addition, the electrochromic properties of PAP film-coated electrodes were examined.