Corrosion inhibition mechanism of imidazole ionic liquids with high temperature in 20% HCl solution

Background This paper focuses on the chemical and physical adsorption of 1-hexyl-2,3-dimethyl imidazolium bromide (HDMIMBr), 1-decyl-2,3-dimethyl imidazolium bromide (DDMIMBr), and 1-hexadecyl-2,3-dimethyl imidazolium bromide (C16DMIMBr) on the surface of mild steel at high temperature in order to explore the mechanism of a corrosion inhibitor in a complex environment. Methods Gravimetric, scanning electron microscope, X-ray photoelectron spectroscopy, and electrochemical tests explored the corrosion inhibition performance from the experimental level. Quantum chemical calculations and molecular dynamics simulations reveal the corrosion inhibition mechanism from the molecular scale. Results The results show that the longer the alkyl chain of the three corrosion inhibitors studied, the better the corrosion inhibition performance. This is due to the hydrophobic effect of the long alkyl chain, which has its own synergistic effect and then self-assembles to form an adsorption film with a multilayer structure. Conclusion This dense adsorption film makes corrosion inhibitors a good application prospect in complex corrosive environments.