An Amino Acid Functionalized Ionic Liquid as A Multifunctional Lubricant Additive in Water-Glycerol

Water-glycerol as one promising alternative for mineral oil can be applied as a green lubricant but has poor lubricity and strong corrosivity. It is desirable to design multifunctional water soluble lubricant additives. Protic ionic liquids (PILs) show considerable potential due to their facile preparation and environmental friendliness. Herein, an eco-friendly PIL ([osar][mea]) was facilely prepared from an amino acid derivate and investigated its anticorrosion and lubrication performances in the glycerol solution. Furthermore, the wear traces were measured using SEM/EDS and XPS for exploring the lubrication mechanism. The prepared PIL can rapidly increase the corrosion inhibition ability of water-glycerol as its concentration increases over CMC, and the anion playing a key role in the light of DFT calculations. Furthermore, [osar][mea] can greatly enhance the lubrication capability especially of water-glycerol while its concentration in the glycerol solution exceed 3%. The lubricity reduced with the increasing load. By the means of using SEM/EDS and XPS evaluation of the wear traces, we can speculate the possible lubrication mechanism may be the presence of the [osar][mea] adsorption film and the tribofilm containing complex nitrogen compounds.