Probing the nanofriction of non-halogenated phosphonium-based ionic liquid additives in glycol ether oil on titanium surface

Abstract The nanofrictional behavior of non-halogentated phosphonium-based ionic liquids (ILs) mixed with diethylene glycol dibutyl ether in the molar ratios 1:10 and 1:70 was investigated on titanium (Ti) substrate using atomic force microscopy (AFM). A significant reduction is observed friction coefficient μ for IL-oil mixtures a higher IL concentration (1:10, ∼ 0.05), compared to that lower ( 0.1). AFM approaching force-distance curves number density profiles revealed preferred accumulate at surface forming IL-rich layered structures. ordered layers formed facilitated nanoscale by preventing direct surface-to-surface contact. However, disappeared case concentration, resulting an incomplete boundary layers, because ions were displaced molecules oil during sliding be less efficient reduction.