Improving tribological properties of oil-based lubricants using hybrid colloidal additives

Abstract Colloidal particles and ionic liquids (ILs) are emerging as potential additives for enhancing lubricant performance. We examine a hybrid system containing colloidal suspensions of hairy silica particles (HSPs) in an IL and motor oil. HSPs swollen in IL lower the sliding friction between steel ball-plate tribopairs at room temperature, while the addition of HSP/IL into motor oil at 100 °C dramatically impacts wear and lubrication. This included prevention of significant noise and scuffing from occurring in the tribometer when using motor oil alone. The outstanding performance of the HSP/IL to modulate friction and wear suggests such hybrid lubricants have potential to be the basis for a new class of tuneable friction modifiers to low-viscosity ‘energy efficient’ lubricants.