Electrochemical and molecular simulation studies on the corrosion inhibition of L-glutamine monolayers on an iron surface

L-Glutamine was used to form monolayers for the inhibition of the corrosion of iron in 0.50 mol dm-3 H2SO4. The protection ability of the films was examined by electrochemical impedance spectroscopy. The mechanism of adsorption is discussed using quantum chemical calculations and molecular simulations. Scanning electron microscopy was applied to confirm the forma- tion of L-glutamine monolayers and the inhibitive effect. The results indicate that the molecules of L-glutamine are able to form films on the surface of iron and longer immersion time of the iron electrode in the solution results in a stronger inhibition ability of the films. The films are formed spontaneously by the adsorption of L-glutamine with a specific affinity of its head-group to the iron surface, hence, the densely and ordered monolayers can be considered as self-assembled.