Friction heat-driven robust self-lubricity of n-alkanols/epoxy resin coatings enabled by solid-liquid phase transition.

Due to the inherent damage effect, friction heat is commonly undesirable yet inevitable in moving components. Hence, obtaining robust running of mechanical assemblies under high sliding velocity is challenging. Herein, we report an alternative strategy to design robust self-healing lubricity materials by taking advantage of friction heat-driven solid-liquid phase transition employing facile coatings of n-alkanols/epoxy resin. The lubricity performance of composite coatings increased with sliding velocity, leading to a low friction coefficient (0.066) and wear rate (1.968 × 10-7 mm3 N-1 m-1) under 5000 rpm. The low friction was mainly attributed to the controlled phase-transition characteristics of n-alkanols, which absorbed friction heat to release liquid n-alkanols for maintaining intelligent shear interfaces. The low wear was ascribed to the high load-bearing capacity and self-healing property of composite coatings. Our study may guide a common framework to rationally design self-healing lubricant materials via solid-liquid phase transition by utilizing the undesirable (yet inevitable) friction heat. Our approach could achieve the robust, ultralow friction and wear of moving components under harsh working conditions.