Laser manufactured-liquid metal nanodroplets intercalated Mxene as oil-based lubricant additives for reducing friction and wear

Two-dimensional (2D) material MXene is a research hotspot in lubricating materials because of its unique layered structure, which provides weak interlayer interaction and easy shear ability. Herein, the liquid metal nanodroplets intercalated MXene were successfully prepared via pulsed laser treatment and self-assembly method. First, zero-dimensional (0D) nano gallium-based liquid metal (GLM) was synthesized by pulsed laser irradiation of bulk Ga80In20 in acetone. Then, the GLM nanodroplets were loaded onto 2D MXene nanosheets via the effect of electrostatic adsorption to prepare MXene@GLM composite material. The as-obtained GLM not only widens the interlayer distance between MXene nanosheets, making it more susceptible to interlayer shear, but also enhances its lipophilicity. The friction test results showed that the MXene@GLM has the best lubrication performance with 1.0 wt% additive. The coefficient of friction (COF) of base oil PAO-6 can decrease from 0.79 to 0.097, the wear volume is reduced by 90.3%, and the maximum load sustained reaches 950 N. The good tribological properties are mainly owing to the synergistic lubrication of GLM and MXene, which can form a continuous and firm tribofilm on the friction contact surface and avoid the direct contact of the friction pair.