Potentiodynamic fabrication and characterization of poly(4-amino-3-hydroxynaphthalene sulfonic acid) modified glassy carbon electrode

Electropolymerization technique is an effective to control the thickness of the conducting polymer film. Poly (4-amino-3-hydroxynaphthalene sulfonic acid), as polymer of aniline derivative, synthesized potentiodynamically on surface of glassy carbon electrode, experienced catalytic property towards several electroactive alkaloids and pesticides in our previous reports. However, controversial arguments on whether the reported catalytic property is due to the deposited polymer film, activation of the surface during scanning the electrode in acidic medium, or the monomer itself have not been addressed. Thus, this paper describes properties of the polymer film modified electrode as compared to unmodified glassy carbon electrode, activated glassy carbon electrode, pretreated glassy carbon electrode, and monomer casted glassy carbon electrode. The effective surface area, film thickness, elemental composition, circuit elements including charge transfer resistance & double layer capacitance, and morphology determined using cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron microscopy- equipped with an energy dispersive spectrometer, atomic force microscopic, and x-ray photoelectron spectroscopic techniques as applicable confirmed the modification of the surface of the glassy carbon electrode with a conductive, electroactive, nano-sized (40-60 nm) polymer film that increased the effective surface area of the modified electrode (PGCE). The authors are now confident to conclude that the observed catalytic property of the polymer modified glassy carbon electrode towards the analytes in our reported works is thus solely due to the synergetic effects of properties of the deposited redox polymer film on the electrode surface.