The effect of counter ions and substrate material on the growth and morphology of poly(3,4-ethylenedioxythiophene) films: Towards the application of enzyme electrode construction in biofuel cells

Poly(3,4-ethylenedioxythiophene) (PEDOT) films, with Cl^?, NO₃^?, poly(styrene sulfonate) (PSS^?) or carbon nanotubes (CNTs) as counter ions, were electrochemically deposited onto indium tin oxide (ITO) glass from aqueous electrolyte. PEDOT film, with tetrafluoroborate anions (BF₄^?) as counter ions, was also electrochemically deposited on ITO glass from a propylene carbonate-based electrolyte. The effect of counter ions on the morphology of PEDOT films was demonstrated by the characterizations with scanning electron microscope (SEM). Different carbon-based materials were explored as the substrate materials for PEDOT film generation in electropolymerization, including carbon ink paper, carbon paper, carbon felt, and reticulated vitreous carbon foam (RVC foam). The micro-structure and the surface morphology of the resulted PEDOT films were imaged with SEM. The elemental analysis of the films was performed with energy dispersive X-ray analysis (EDAX). The topography of the PEDOT films was characterized using confocal white light microscopy (COM). A biofuel cell cathode was prepared by immobilization of Trametes Hirsuta laccase (Th-laccase) in PEDOT and the performance of the electrode towards oxygen reduction was examined by chronoamperomentric measurements.