Enhancing the tribological performance of Ti3C2 MXene modified with tetradecylphosphonic acid

MXene is a new two-dimensional (2D) material with excellent physical and chemical properties. However, the MXene nanosheets have high surface energy and exhibit poor dispersibility and stability in oil, owing to the presence of -OH, -O, and -F functional groups on the surface. Herein, 2D Ti3C2 MXene material was chemically modified with tetradecylphosphonic acid (TDPA). Through the condensation reaction of the phosphoric acid groups with hydroxyl groups on the Ti3C2 surface, a modified Ti3C2 nanosheet (TDPA-Ti3C2) was obtained. We dispersed TDPA-Ti3C2 into castor oil to study its tribological properties. Compared with pure castor oil, the coefficient of friction (COF) and wear rate (Wr) of castor oil with 0.1 wt% TDPA-Ti3C2 are reduced by 27.9% and 55.1%, respectively. The possible friction-reducing and anti-wear mechanisms of TDPA-Ti3C2 in castor oil were explored by analyzing the surface morphologies of the wear scars. The improvement of lubrication performance is attributed to the deposition and adsorption of TDPA-Ti3C2 on the friction surface during the lubrication process, forming a physical transfer film to prevent direct contact with the friction pair. The research results show that the modified Ti3C2 has broad application prospects in lubrication and tribology.