Electrochemical incorporation of graphene oxide into conducting polymer films

In this paper we report a simple, one-step method for direct electrochemical incorporation of graphene oxide (GO) into conducting polymer films without the use of any additional dopants. Polypyrrole (PPy) and poly(3,4-ethylenedioxythiophene) (PEDOT) were successfully electropolymerized in as-prepared aqueous GO dispersions using potentiostatic polymerization. When dispersed in water, the GO flakes carry a negative surface charge which allows them to serve as counter ions and hence be incorporated into the polymer films during electropolymerization. The incorporation of GO was verified using XPS whereas vibrational spectroscopy was used to confirm the successful formation of the two conducting polymers. The surface morphologies of the polymer-GO films were investigated with SEM. The incorporation of GO into PPy resulted in a distinctly different and more porous surface morphology than that observed in PPy films synthesized in the presence of conventional counter ions. The PEDOT-GO film, on the other hand, had a very smooth surface morphology similar to that of PEDOT films polymerized in the presence of other polyanions. As these composite films are aimed for electrochemical device applications, their redox behavior and electrochemical capacitance properties were also investigated using cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The polymer-GO films exhibited good electrochemical reversibility during cycling in 0.1 M KCl. The PPy films exhibited high redox capacitance regardless of the counter ion used in electropolymerization whereas PEDOT-GO had lower redox capacitance than PEDOT-PSS.