Deactivation of poly(o-aminophenol) film electrodes by storage without use in the supporting electrolyte solution and its comparison with other deactivation processes. A study employing EIS

The effect of storage time without use (STWU) in the supporting electrolyte solution on the charge-transport parameters of poly( o -aminophenol) (POAP) film electrodes was studied by electrochemical impedance spectroscopy. STWU decreases the charge-transport rate of the polymer. This effect is herein called deactivation. Impedance diagrams of both nondeactivated and deactivated films in contact with a solution containing the p -benzoquinone/hydroquinone redox couple were interpreted on the basis of a model formulated for homogeneous conducting polymers, where the bathing electrolyte contains a redox pair that provides the possibility for electrons to leak from the film surface. Dependences of diffusion coefficients for electron ( D e ) and ion ( D i ) transport and interfacial resistances related to ion R i f | s and electron R m | f , R e f | s transfer across the polymer/solution and metal/polymer interfaces, respectively, on the degree of deactivation ( θ d ) of the polymer were obtained. These dependences were compared with those from previous work for POAP films deactivated by employing other procedures, such as high positive potential limits, soaking in a ferric ion solution, and prolonged potential cycling.