Amphiphilic Lubricants Linked by Hydrogen Bonds Achieve Superlubricity and Enhance Water/Oil Tribological Properties

Glycerol is immiscible with oils, which poses a fundamental limitation in the development of glycerol-based lubricants suitable for nonpolar environments. In this study, pyrolyzed glucose was mixed with glycerol. The oxygen-containing functional groups in the pyrolysis products formed a dense network of hydrogen bonds with the glycerol molecules, thereby creating a stable amphiphilic fluid that overcomes this classic incompatibility. This fluid not only mixes with both polar and nonpolar media but also exhibits macroscopic superlubricity on a glass/Si₃N₄ friction pair. Importantly, the running-in period was extremely short (<4 s), and after 10 h of continuous operation, virtually no wear marks were detected on the glass surface. Mechanistic studies indicate that the superlubricity behavior stems from the synergistic interaction between the adsorbed film and the tribochemical film, and that the hydrogen-bond network effectively enhances the load-bearing capacity of the lubricating film. Furthermore, in a steel/steel friction pair under a contact pressure of 1.27 GPa, when used as an oil-based additive, the wear rate in the wear zone on the steel disc surface was reduced by 63.3% compared with PAO6; when used as a water-based additive, the wear rate was reduced by 55.5%. This work provides a new approach for developing amphiphilic liquid superlubricants with ultrashort motion cycles, which is expected to advance the practical application of sustainable lubrication technologies in a wider range of engineering scenarios.