Tribological properties and mechanism of Mo₂Ti₂C₃ enhanced self-healing zwitterionic polymer

Self-healing polymer lubricating materials can effectively extend the service life of engineering lubricants. However, their development and application in engineering face serious challenges due to inherent defects such as large friction coefficients and easy wear. In this study, a self-healing nanocomposite (Mo₂Ti₂C₃/DMcA) with low wear, high thermal conductivity, and superior lubricity was developed by incorporating Mo₂Ti₂C₃ MXene as a solid lubricant into a zwitterionic polymer-based solid lubricating matrix. Experimental results demonstrated that the composite with 1.0 wt% Mo₂Ti₂C₃ exhibited optimal friction-reduction and anti-wear performance. Compared to the pristine polymer matrix, the composite achieved a 47.9 % reduction in the coefficient of friction and a 91.7 % decrease in wear rate. The composite coating showed good thermal conductivity, and the surface temperature reached 52.8℃ in 10 s when exposed to the ambient temperature of 60℃. Furthermore, the Mo₂Ti₂C₃/DMcA nanocomposite displayed remarkable self-healing capabilities, achieving complete recovery of surface wear scars and scratches within 3 h under 25°C and 80 % RH. This study reveals that Mo₂Ti₂C₃ MXene serves as an ideal additive for enhancing the tribological properties of polymers, significantly broadening the application prospects of Mo₂Ti₂C₃/DMcA composites in advanced friction materials.