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 (Mo 2 Ti 2 C 3 /DMcA) with low wear, high thermal conductivity, and superior lubricity was developed by incorporating Mo 2 Ti 2 C 3 MXene as a solid lubricant into a zwitterionic polymer-based solid lubricating matrix. Experimental results demonstrated that the composite with 1.0 wt% Mo 2 Ti 2 C 3 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 Mo 2 Ti 2 C 3 /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 Mo 2 Ti 2 C 3 MXene serves as an ideal additive for enhancing the tribological properties of polymers, significantly broadening the application prospects of Mo 2 Ti 2 C 3 /DMcA composites in advanced friction materials.