Anticorrosion performance assessment of silane-modified chitosan/epoxy primer coatings on mild steel in saline environment using computational simulation techniques

The anticorrosion performance of silane-modified chitosan/epoxy primer coatings was evaluated using quantum chemical computations (QCC) and molecular dynamics simulation (MDS) techniques. The objective was to appraise the molecular/atomistic level performance of silane-modified chitosan/epoxy primer coating system on mild steel in saline water to be able to design robust anticorrosion epoxy nanocomposite primer coating for marine application. The QCC showed that quantum parameters for (3-aminopropyl) trimethoxy silane-modified chitosan nanocluster (AMCN) are optimum and therefore correspond to high corrosion protective capability. The adsorption energies (E_ads) for AMCN/epoxy, tetraethoxysilane-modified chitosan/epoxy, chitosan-modified epoxy, and unmodified epoxy coatings were found to be - 3094.65, - 2,630.00, - 2,305.77, and - 1,189.33 kcal/mol, respectively. The high negative value of E_ads indicates the coating molecules interacted and adsorbed strongly on the mild steel surface. Hence, AMCN/epoxy coating is potentially most corrosion-resistant than the others. Further, it is established that shorter bond length corresponds to higher bond strength and therefore indicates chemical interaction. Thus, the radial distribution function showed the bond lengths between atoms of the AMCN and mild steel surfaces were shorter than those of other molecules. Overall, AMCN/epoxy coating molecules possess good anticorrosion properties and therefore would perform well if deployed for service in saline environments.