Assessment of ZnO-doped polyaniline/Prunus domestica reinforced paint for corrosion protection of mild and stainless steel

There has been an increasing interest in the production of metal/metal oxide-doped conducting polymers-based composites with natural materials for application as corrosion resistant coatings on steel and other precious metals. Herein, the corrosion inhibition performance of zinc oxide-doped polyaniline/Prunus domestica gum (ZnO/PANI/PDG) is reported. The composites, soluble in variety of organic solvents, were prepared by emulsion polymerization of aniline in the presence of ZnO and PDG. UV-visible-NIR and FTIR spectroscopy validated the formation of composite, XRD analysis revealed the amorphous texture while SEM analysis showed broccoli-like morphology. Electrochemical behavior was studied through cyclic voltammetry (CV) showing a pair of redox peaks. The as-synthesized composites were applied for the corrosion inhibition of mild (MS) and stainless steel (SS) in 3.5% NaCl and 1 M H₂SO₄ solution. The inhibition efficiency of composite-coated MS and SS was recorded as 81.68% and 97.68% for SS in saline medium, respectively, while the inhibition efficiencies of ZnO/PANI/PDG-coated MS and SS were 99.84 and 99.50%, respectively, in 1 M H₂SO₄. The effect of ZnO/PANI/PDG was also checked on corrosion inhibition property of selected paint both on MS and SS in the form of uniform blend of composite/paint mixture in saline and acidic medium. The composite enhanced the corrosion inhibition efficiency of paint by reducing the corrosion rate through synergistic effect. The corrosion inhibition efficiency of composite/paint blend-coated MS and SS was observed to be 99.99% both in saline and acidic medium. The results were also validated through open-circuit potential measurement and EIS analysis.