Multidentate Hydrogen‐Bonded Semisolid Oil‐Based Lubricants for Durable Macroscale Superlubricity Across Ambient and Vacuum Environments

ABSTRACT Macroscale superlubricity (µ < 0.01) has attracted extensive interest for minimizing friction and wear; however, oil‐based systems capable of maintaining stable superlubricity under harsh environments remain rare due to creep, leakage, and poor vacuum adaptability. Here, a multidentate hydrogen‐bond‐engineered semisolid lubricant (OA–SP60) is developed through the supramolecular assembly of oleic acid (OA) and sorbitan monostearate (SP60). Cooperative hydrogen‐bonded clustering induces a stabilized semisolid structure, enabling enhanced structural stability, suppressed leakage behavior, and robust interfacial lubrication under both ambient and vacuum environments. OA–SP60 achieves durable macroscale superlubricity at steel/polytetrafluoroethylene (PTFE) interfaces with an ultralow friction coefficient of 0.006, a wear reduction of 95.4% relative to dry sliding, and stable operation exceeding 100 000 cycles. Notably, the superlubric state is fully maintained under high vacuum (∼3 × 10 −3 Pa) with negligible mass loss (0.09%), demonstrating excellent vacuum compatibility. Experimental characterizations combined with theoretical simulations reveal that multidentate hydrogen‐bonded clusters promote persistent interfacial adsorption and structural stabilization, thereby sustaining long‐term superlubricity. In addition, the semisolid architecture effectively suppresses the creep and leakage commonly encountered in conventional liquid lubricants. This work provides a molecular design strategy for semisolid oil‐based superlubricants and offers insights into interfacial lubrication for practical and vacuum tribological systems.