Experiments and Molecular Simulations to Study the Role of Coadsorption of Oil in Corrosion Inhibitor Films in Improving Corrosion Mitigation

While both field experience and laboratory experiments have shown that the efficiency of adsorbed corrosion inhibitor films improves upon exposure of the aqueous solution to a hydrocarbon phase, a credible explanation of these results is lacking. Using a combination of experiments and molecular simulations, this study examines how exposure to oil molecules affects the nature of adsorbed corrosion inhibitor films on metal surfaces. It is found that oil molecules get coadsorbed in the corrosion inhibitor films, making them more hydrophobic, structurally more ordered, and well packed. Corrosion inhibitor molecules with a bulky polar head adsorb in nonplanar, cylinder-like morphologies. Coadsorption of oil molecules changes the morphology of these films to a planar self-assembled monolayer.