Protective properties of PEDOT/ABA coatings deposited from micellar solution on stainless steel

Abstract

Composite coatings, consisting of combinations of the conducting polymer poly(3,4-ethylenedioxythiphene) (PEDOT) and 4-aminobenzoic acid (ABA), were electrodeposited on glassy carbon and X20Cr13 stainless steel by cyclic voltammetry, using a sodium dodecylsulfate (SDS) micellar aqueous solution of EDOT and ABA as a reaction medium. The coating deposition potential range, scan rate and composition of modification solution were determined. The protective properties of the resulting films on stainless steel were investigated in acidified (pH=4) 0.25 M sulphate solution in the absence and in presence of 0.5 M chloride ions. Diagnostic experiments include measurements of open circuit potential versus exposure time and potentiodynamic polarisation tests. Morphology of the obtained composite coatings was examined using optical metallographic microscope. The composite coatings provide good adherence to the steel substrate and very effective steel corrosion protection. The PEDOT/ABA coatings allow to stabilize the steel corrosion potential within the passive region both in absence and in presence of chloride ions.