Corrosion inhibition of copper by oxalohydrazide and its methylated derivatives: A theoretical study

This research pioneers a computational approach to design superior copper corrosion inhibitors by systematically exploring the impact of targeted methylation on oxalohydrazide (OXH). Leveraging density functional theory (DFT) and molecular dynamics (MD) simulations, we demonstrate that strategic methylation, particularly at the N' positions, significantly amplifies the adsorption energy of OXH derivatives on the Cu (111) surface, favoring a highly stable parallel adsorption mode. Beyond mere adsorption strength, we unveil the precise electronic mechanisms driving enhanced inhibition: calculated HOMO-LUMO energy gaps, hardness, and softness values reveal that methylated derivatives possess markedly improved electronic properties compared to OXH, directly correlating with enhanced corrosion protection. Furthermore, our MD simulations, conducted in an aqueous environment, uncover the nuanced interplay between water molecules and protonated inhibitors, providing critical insights into their real-world performance. This study establishes a novel, predictive framework for tailoring molecular structures to achieve optimal corrosion inhibition, offering a powerful tool for developing next-generation protective coatings for copper-based materials.