Surface Modification of Mild Steel with Thermally Cured Antibacterial Poly(vinylbenzyl chloride)–Polyaniline Bilayers for Effective Protection against Sulfate Reducing Bacteria Induced Corrosion

With the objective of developing anticorrosive conductive polymeric coatings to combat microbially induced corrosion (MIC), a facile and green synthesis approach based on a thermally induced reaction was described. Thermal curing of polyaniline (PANI) was carried out from the silanized mild steel (MS) surface containing reactive epoxy groups, followed by thermally induced N-alkylation of PANI by hydrophobic 4-vinylbenzyl chloride (VBzCl) to produce biocidal functionality. The so-synthesized MS coupons with hydrophobic poly(vinylbenzyl chloride) (PVBC)–quaternized PANI bilayer coatings were investigated for their anticorrosive and antibacterial properties toward biocorrosion induced by sulfate-reducing bacteria (SRB). Antibacterial assay results revealed an evident decrease in the bacterial attachment and the formation of biofilm. The QPANI–PVBC bilayer coatings showed a high corrosion resistance (inhibition efficiency >97%) and stability to resist SRB-induced corrosion. Thus, the QPANI–PVBC bilayer coated MS substrates can be used as effective polymeric coatings to protect the steel-based equipment in corrosive marine environments.