Investigation on the interfacial behavior of polyorganic inhibitors on a metal surface by DFT study and MD simulation

Highlights: • Theoretical calculation is an effective way for choosing corrosion inhibitors. • DFT and MD were used to study the effect of PEG and PAM. • The effect of degree of polymerization on adsorption behavior was studied. • The study may provide a theoretical basis and guidance for further experiments. Metal corrosion is an important technical problem often encountered in industrial production in various fields. One of the efficient and economical methods to effectively block corrosion is to add a corrosion inhibitor, which forms a protective film on the metal surface. Accordingly, environmentally friendly organic corrosion inhibitors have become research hotspots in recent years. Among them, polyorganic substances have been proved to be effective corrosion inhibitors; however, research on this topic is still scarce. In this study, (poly) ethylene glycol and (poly) acrylamide are investigated as polyorganic inhibitors by density functional theory and molecular dynamic simulation, and the effect of the degree of polymerization (DP) on the adsorption behavior on metal surfaces is theoretically analyzed. On the basis of a comprehensive evaluation of their stability and adsorption energy, the optimal DPs of these two inhibitors are determined. This work may provide a theoretical basis and guidance for further research of corrosion inhibitor.