The tribological studies of a new ionic liquid deep eutectic solvent as oil-soluble additive

Ionic liquids (ILs) are characterized by their exceptional friction reduction and anti-wear properties, especially those with simple structures and low melting points, which broaden their applicability. In this work, a low melting point binary ionic liquid was designed by simply blending two solid ILs together at room temperature, resulting in a new ionic liquid deep eutectic solvent (IL-IL DES). Molecular dynamics simulation provided further insights into the formation mechanisms of IL-IL DES by analyzing the interactions within the system. Tribological tests confirm that IL-IL DES with good oil-solubility significantly improve the lubrication performance of base oil when used as additive. Notably, the IL-IL DES phosphorus content in base oil was half that of its individual components, yet it maintained substantial friction reduction effect. Furthermore, IL-IL DES still maintains good lubrication performance in a wide temperature range (−20 °C to 150 °C), which can effectively meet the operational conditions of most mechanical components.