IR drop studies of poly(aniline)-based modified electrodes

Abstract This manuscript presents the electrochemical impedance spectroscopy study regarding the influence of the pH and the range of the applied potential on the IR drop of polyaniline – Gum arabic/graphene oxide (PANI-GA/GOx) electrodes modified by the Layer-by-Layer technique. Using the equivalent circuit modeling methodology, it was discussed the IR drop dependence on parameters such as series and charge-transfer resistances and the double-layer capacitance. Series resistance related to the (PANI-GA/GOx) film conductivity showed to be very influenced by the pH, where a lower value of pH favored the protonation of the polyaniline-based film, increasing the overall conductivity leading to lower values of IR drop. Moreover, the IR drop also showed to be dependent on the range of the applied potential, reflecting in a change at the electrode/electrolyte interface, where an increase at the charge-transfer resistance was found at higher potentials, probably due to the pernigraniline state of PANI.