Water-Resistant Supramolecular Eutectogel Lubricant with MoS₂: Thixotropic Behavior and High-Efficiency Lubrication

The development of supramolecular gel lubricants with excellent rheological properties is critical for high-performance lubrication. Although hydrophobic deep eutectic solvents (HDESs) have shown considerable potential as lubricants, eutectogels containing HDESs remain largely unexplored. Herein, we report the first water-resistant supramolecular eutectogel based on HDES, exhibiting an outstanding thixotropic behavior and lubrication performance. Notably, MoS2 flakes incorporated within the obtained supramolecular eutectogel exhibit uniform dispersion and long-term stability without aggregation, yielding a highly stable composite supramolecular eutectogel. As prepared supramolecular eutectogels without and with MoS2 flakes display excellent water-resistant properties, showing negligible changes after being immersed in water for more than 9 months. Both the eutectogel and its MoS2-doped counterpart exhibit characteristic shear-thinning behavior and remarkable thixotropy with instant and reversible sol-gel transitions. Importantly, these superior rheological properties persist at -10 °C. These thixotropic properties ensure the formation of a stable tribofilm throughout the friction process, effectively reducing the shear strength of friction-pair surfaces and promoting relative sliding. As a result, the MoS2-doped eutectogel achieves a low coefficient of friction (COF), with an average value of 0.07. Moreover, the MoS2-doped supramolecular gel lubricant significantly enhances antiwear performance while sustaining excellent lubrication effects in a simulated locking mechanism of landing gear. This work provides valuable insights for developing green and higher-performance supramolecular gel lubricants, offering potential solutions to the limitations of conventional lubricants.