DOSS– Based QAILs: As Both Neat Lubricants and Lubricant Additives with Excellent Tribological Properties and Good Detergency

Abstract

DOSS– (dioctyl sulfosuccinate) based quaternary ammonium ionic liquids (QAILs) were synthesized and used as both neat lubricants and lubricant additives. The influence of structure on their miscibility, thermal stability, and tribological property was discussed. These QAILs are low cost as compared with conventional halogen-containing ionic liquids (ILs). They are noncorrosive and hydrolysis stable because of their halogen-free characteristics. The tribological properties of these QAILs as neat lubricants for steel/steel and steel/copper contacts are found to be better than conventional halogen-containing ILs 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (L-F104) and far better than traditional synthetic lubricant poly-α-olefin (PAO). Moreover, oil-soluble ILs were obtained by properly adjusting the chain length and cation asymmetry of these QAILs, which can be easily dissolved in nonpolar synthetic-oil PAO. They are found to be effective lubricant additives for improving the friction-redu...