Deep Eutectic Solvent-Modified MXene as Nonpolar Lubricant Additives

Deep eutectic solvents (DESs) serve as functionalized solvents with superior lubricating properties. However, limited research has been conducted on their application for modifying and treating nanomaterials as nonpolar lubricant additives. Consequently, this paper presents the synthesis of a menthol/thymol/tetradecylphosphonic acid oil-soluble ternary DES, which was employed to modify and treat MXene. The DES facilitates the expansion of MXene’s interlayer spacing, while the grafting of long carbon chains in the DES enhances the dispersion stability of MXene in nonpolar lubricants. Furthermore, the tribological properties of DES complexed MXene lubricant additives were examined, revealing a reduction in the coefficient of friction and wear rate by 46.6 and 56.8% for both 0.1 wt % DES/MXene and 2 wt % DES base oil at 25 °C, and by 40.3 and 48.1% at 100 °C, respectively. The superior lubrication performance is attributed to optimal dispersion stability, exceptional wettability, and the synergistic impact of the dual lubrication film created by DES and the interlayer shear mechanism of MXene.