In Situ Self‐Healing Triggered by Reversible Dynamic Hydrogen Bonds for Near‐Zero Wear of MXene Supramolecular Films

ABSTRACT Achieving simultaneous macroscale superlubricity and near‐zero wear remains a formidable challenge in the design of next‐generation solid lubricants. In practical engineering systems, the realization of macroscale superlubricity is often accompanied by irreversible material loss, leading to increased wear rates and reduced service lifetimes. To address this challenge, a supramolecular composite lubricant film composed of citric acid (CA)–chitosan (CS) functionalized Ti 3 C 2 T x MXene (CA–CS@MXene) was fabricated. This CA–CS@MXene film exhibits macroscale superlubricity (friction coefficient ∼0.006) and a near‐zero wear rate under 50% relative humidity. This extraordinary behavior arises from a humidity‐driven transition of interlayer interactions, where static strong hydrogen bonds among Ti 3 C 2 T x MXene nanosheets are converted into dynamic, weak, and rapidly exchangeable ones. Such a transformation lowers the interlayer sliding energy barrier and enhances hydrogen‐bond‐mediated structural reconstruction, enabling real‐time self‐healing under frictional stress. This work offers new insights into the design of solid lubricants that combine macroscale superlubricity and self‐healing capabilities, and demonstrates broad applicability in representative mechanical components such as planar bearings, spur gears, spherical bearing inner rings, and flexible rubber substrates.