An intelligent feedback loop for sustaining self-lubrication and wear resistance

Abstract

Abstract Intelligent materials that self-sense and self-adjust are an emerging frontier in sustainable technology. Here we introduce a Cu/C nanocomposite film that acts as a self-adjusting intelligent lubricant. In this film, frictional heating triggers melting and migration of Cu nanoparticles along nanopores to the friction interface, where the Cu catalyzes the in-situ formation of ordered carbon nanostructures. Real-time monitoring of friction coefficient ( μ ), electrical resistance ( R ), and metal release confirms a feedback loop: high friction generates enough heat, melting the metal nanoparticles; the migrating metal then lowers friction by creating low-friction nanostructures, which reduces heat and arrests further migration until friction rises again. This self-limiting feedback enables stable ultra-low friction ( μ  ~ 0.04) and an exceptional wear life (>40 km) even in high vacuum. By utilizing friction-derived heat as an intrinsic activation signal, our system establishes a general paradigm for intelligent, self-adjusting materials with applications extending beyond tribology.