Oil-containing self-lubricating composite material is an effective approach to address the wear issues of polymer materials. In this work, the traditional lubricant 500SN was encapsulated within melamine-formaldehyde (MF) resin shells through in-situ polymerization to prepare 500SN@MF microcapsules. Comprehensive characterizations confirmed that the 500SN@MF microcapsules have a well-defined spherical morphology, improved thermal stability, and excellent compatibility with phenolic epoxy resin. The 500SN@MF microcapsules were mixed with phenolic epoxy and cured at room temperature to form a composite self-lubricating coating. Tribological performance tests demonstrated that the composite coating exhibited exceptional anti-wear and friction-reducing properties, with a friction coefficient (COF) of ~0.038 and a notably low wear rate of 0.077×10⁻⁶ mm³/(N·m) under 5 N load and 20000 friction cycles. Significantly, the 500SN@MF microcapsules could be produced in small batches while maintaining an intact core-shell structure, which offers a scalable material solution for achieving efficient, long-term lubrication in mechanical components and significantly extending their service life.

Perfluoropolyether (PFPE) oils pose challenges in terms of their compatibility with nanoparticle lubrication additives because of their unique molecular structure, limiting their lubrication performance enhancement. To address this issue, we propose the development of nanoparticle composite supramolecular gel lubricants, aiming to maintain the dispersion stability of molybdenum disulfide (MoS₂) nanoparticles within PFPE lubricants. This was achieved by harnessing the self-assembled three-dimensional (3D) network structure of supramolecular gels to entrap MoS₂ nanoparticles. The MoS₂ nanoparticles tended to cluster and settle in PFPE oils. However, the MoS₂-composite PFPE supramolecular gel lubricant (gel@MoS₂) exhibited exceptional dispersion stability over an extended period. MoS₂ nanoparticles used as additives in PFPE-based supramolecular gel lubricants not only enhanced the mechanical strength but also retained outstanding thixotropic properties. Additionally, nanoparticles improved the extreme pressure performance, anti-friction capabilities, and anti-wear properties of PFPE-based supramolecular gel lubricants under a high load of 300 N. Furthermore, the lubrication mechanism of the gel@MoS₂ composites was elucidated using focused ion beam-transmission electron microscopy and X-ray photoelectron spectroscopy. During the friction process, the 3D networks of the supramolecular gels, held together by weak interaction forces such as hydrogen bonds, halogen bonds, and van der Waals forces, were disrupted under continuous shear forces. Consequently, some of the MoS₂ nanoparticles and gelators migrated to the steel surface, forming a protective lubricating film. This research holds significant importance in prolonging the lifespan of equipment in critical sectors such as aerospace and aviation, where high-end lubrication is essential.

Hydrogels as one kind of soft materials with a typical three-dimensional (3D) hydrophilic network have been getting great attention in the field of biolubrication. However, traditional hydrogels commonly show poor tribology performance under high-load conditions because of their poor mechanical strength and toughness. Herein, pure chemical-crosslinking hydrogels mixed with different types of the micron-scale fibers can meet the requirements of strength and toughness for biolubrication materials, meanwhile the corresponding tribology performance improves significantly. In a typical case, three kinds of reinforcement matrix including needle-punched fibers, alginate fibers, and cottons are separately combined with Poly(n-vinyl pyrrolidone)-poly(2-hydroxyethyl methacrylate (PVP-PHEMA) hydrogels to prepare fibers reinforced composite hydrogels. The experimental results show that the mechanical properties of fibers reinforced composite hydrogels improve greatly comparable with pure PVP-PHEMA hydrogels. Among three kinds of fibers reinforced composite hydrogel, the as-prepared composite hydrogels reinforced with needle-punched fibers possess the best strength, modulus, and anti-tearing properties. Friction tests indicate that the fibers reinforced composite hydrogels demonstrate stable water-lubrication performance comparable with pure PVP-PHEMA hydrogels. Besides, the hydrogel-spunlace fiber samples show the best load-bearing and anti-wear capacities. The improved tribology performance of the composite hydrogels is highly related to mechanical property and the interaction between the fibers and hydrogel network. Finally, spunlace fibers reinforced hydrogel materials with high load-bearing and low friction properties are expected to be used as novel biomimetic lubrication materials.