Characterization and Corrosion Protection Ability of Conducting Polymer Coatings on Mild Steel in Acid Media

Electrochemical polymerization of polythiophene (PTh), polypyrrole (PPy) and polyterthiophene (PTTh) were investigated on mild steel (MS) electrode. Multilayered coating, consisting of combinations of the conducting polymers PTh and PPy, were also investigated on mild steel electrode. Cyclic voltammetry technique was used for all synthesis. The corrosion performance of coated mild steel with different polymers were investigated in 0.5M of different acid solutions (HCl, H3PO4 and HNO3), using open circuit potential (OCP) and potentiodynamic polarization (PP) measurements. All polymeric films protected the substrate against corrosion but the bilayer coating PPy/PTh gave the best protection efficiency in all used acids reaching to 97% in phosphoric acid solution. The obtained coatings were characterized using scanning electron microscope (SEM).