Hydrogels, with their tissue-like properties, biocompatibility, and soft properties, are potential biomimetic cartilage replacement materials. However, the conflict between their surface lubricity and load-bearing properties significantly limits their application. Here, we developed a structure-based hydrogel with super-lubricity and high load-bearing properties. Through ultraviolet (UV)-controlled dissociation, a gradient hydrogel surface was constructed. This structure effectively dissipates normal contact stress while maintaining a high surface hydration level, enhancing load-bearing capacity. Furthermore, micron-sized spherical gel particles were prepared using an emulsion method and incorporated into the highly hydrated polymer network, further enhancing the load-bearing capacity of the porous hydrogel and significantly reducing the coefficient of friction (COF) by converting sliding friction into rolling friction. Ultimately, through multiple synergistic effects, we achieved ultra-low friction performance, with a COF of approximately 0.0064 after 20,000 cycles under a 5 N load. This innovation provides an alternative solution for future biomimetic articular cartilage.

Self-lubricating fabric liners are the core functional materials of self-lubricating joint bearings and have garnered significant attention in the field of high-tech equipment lubrication because of their excellent characteristics, such as impact resistance, corrosion resistance, and high load-bearing capacity. This review summarizes recent progress in tribological research on self-lubricating fabric composites, covering external parameters, woven structures, reinforced fibers, resin matrix designs, and filler/interface modifications. The correlation between the dynamic response of the friction interface (friction coefficient (COF), wear rate) and the macroscopic mechanical behavior (load-carrying capacity, fatigue resistance) of the composites was systematically revealed through cross-scale analysis. Furthermore, the synergistic effects of multiscale factors on the tribological and mechanical properties of liner materials are elucidated. This provides a theoretical basis and technical guidance for developing high-performance self-lubricating fabric liners with high wear resistance and low friction fluctuations, effectively improving the efficiency of engineering applications of such materials under extreme load, temperature, and medium conditions.

In this study, a polymer gelator containing urea groups and dynamic disulfide bonds was prepared using the method of free radical aggregation. When added to base oil, it formed a tight and dynamic supramolecular network structure through the synergistic effect of dynamic covalent and non-covalent, exhibiting excellent mechanical adaptability while improving the heat resistance of lubricating oil. The tribological behavior of the prepared gel lubricants was comprehensively evaluated. The results revealed that the gel lubricants outperformed the base oil, exhibiting markedly lower friction coefficients (COFs), reduced wear rates, delivering exceptional extreme pressure resistance, and maintaining functionality in challenging and severe operating environments. Specifically, the gel lubricants delivered a 30% reduction in COF, 89% decrease in wear volume, and a maximum load-bearing capacity of 1500 N. Moreover, the gel lubricant enhanced the viscoelasticity of the base oil, promoting the formation of both an adsorbed film and a tribochemical protective film at the friction interface, which resulted in good tribological performance under fully lubricated conditions. The gel lubricant delivers exceptional tribological functionality while playing a pivotal role in eliminating environmental hazards caused by creep-induced oil leakage.

Inspired by the rigid vein-flexible membrane hierarchical architecture of dragonfly wings with an exceptional natural system integrating strength, flexibility, and damage tolerance, we designed and fabricated, a robust, multifunctional composite coating (O-H-M) based on polysilazane (OPSZ), hydroxyl-terminated polybutadiene (HTPB), and MXene nanosheets for synergistic lubrication and corrosion protection. This bio-inspired design strategically integrates three complementary components: a rigid OPSZ backbone for structural support and substrate adhesion, flexible HTPB chains that enable energy dissipation via shear deformation and chain slippage, and 2D MXene nanosheets serving dual roles as a solid lubricant and nano-reinforcement. The “self-locking interpenetrating network” formed by chemical crosslinking between OPSZ and HTPB effectively mitigates the inherent brittleness of OPSZ, endowing the coating with remarkable toughness. MXene further enhances load-bearing capacity and wear resistance while constructing a labyrinth barrier against corrosive species. The resulting O-H-M coating achieves an ultralow friction coefficient (˂ 0.1) and a wear rate far reduced by one order of magnitude compared to pure OPSZ. It also exhibits outstanding long-term corrosion resistance, decreasing the corrosion current density of Q235B by three orders of magnitude relative to the bare metal substrate, and maintains robust stability under coupled tribocorrosion conditions. Molecular dynamics simulations reveal that the superior lubricity originates from synergistic effects: the cross-linked network facilitates molecular chain mobility and energy dissipation, while MXene enables interlayer sliding to reduce shear stress. This work offers practical and scalable paradigm for developing next-generation bio-inspired multifunctional coatings that balance mechanical robustness, lubricity, and chemical stability, with great potential for harsh engineering environments.

Two-dimensional materials are excellent lubricants with inherent advantages. However, superlubricity has been reported for only a few of these materials. Unfortunately, other promising two-dimentional (2D) materials with different physical properties cannot be discovered or applied in production; thus, energy consumption can be greatly reduced. Here, we carry out high-throughput calculations for 1,475 2D materials and screen for low-friction materials. To set a standard, we propose, for the first time, a geometry-independent lubricating figure of merit based on the conditions for stick-slip transition and our theory of Moiré friction. For the efficient calculation of this figure of merit, an innovative approach was developed based on an improved registry index model. Through calculations, 340 materials were found to have a figure of merit lower than 10⁻³. Eventually, a small set of 21 materials with a figure of merit lower than 10⁻⁴ were screened out. These materials can provide diverse choices for various applications. In addition, the efficient computational approach demonstrated in this work can be used to study other stacking-dependent properties.

Lubricants are often contaminated by water in different ways. Water-polluted lubricants extremely accelerate wear corrosion, leading to the deterioration of lubricity performance. Recently, multiphase media superwettability has been developed to endow one surface with compatible functions, such as on-demand separation of oily wastewater. However, realizing the robustness of the dual superlyophobic surface to solve water-caused lubricant deterioration and water contamination as needed remains challenges. Herein, a robust dual superlyophobic membrane is presented to realize on-demand separation for various lubricant–water emulsions. Compared to pure lubricants, the purified lubricants have equivalent tribology performance, which are much better than that of water-polluted lubricants. The as-prepared membrane maintains dual superlyophobicity, high-efficient for water or lubricant purification, and excellent tribology performance of the purified lubricant, even after immersion in hot liquids for 24 h, multicycle separation, and sandpaper abrasion for 50 cycles. Water-polluted lubricant extremely accelerates wear corrosion to promote catalytic dehydrogenation of lubricants, generating too much harmful carbon-based debris. This work shows great guiding significance for recovering the tribology performance of water-polluted lubricants and purifying water by the dual superlyophobic membrane.

The issues regarding energy dissipation and component damage caused by the interface friction between a friction pair attract enormous attention to friction reduction. The key-enabling technique to realize friction reduction is the use of lubricants. The lubricants smooth the contact interfaces, achieving an ultralow friction contact, which is called superslippery or superlubricity. At present, superslippery and superlubricity are two isolated research topics. There is a lack of unified definition on superslippery and superlubricity from the viewpoint of tribology. Herein, this review aims at exploring the differences and relations between superslippery and superlubricity from their origin and application scenarios. Meanwhile, the challenges for developing superslippery surface and superlubricity surface are discussed. In addition, perspectives on the interactive development of these two surfaces are presented. We hope that our discussion can provide guidance for designing superslippery or superlubricity surfaces by using varies drag-reduction technologies.

Triboelectric nanogenerator (TENG) based on triboelectrification has attracted wide attention due to its effective utilization of green energy sources such as marine energy. However, researches about liquid–liquid triboelectrification are still scanty as solid–liquid triboelectrification has been widely studied. Herein, this work focuses on the hydrophobic/slippery substrate–water interfacial triboelectrification based on the solid friction materials of polytetrafluoroethylene (PTFE) nanoparticles. The hydrophobic/slippery substrate–water interfacial triboelectrification are studied by assembling PTFE coated Al sheets and perfluoropolyether (PFPE) infused PTFE coated Al sheets (formed the slippery lubricant-infused surfaces (SLIPSs)) as the friction electrode, and water as liquid friction materials, respectively. The results show that the hydrophobic TENG output performances improved as the PTFE nanoparticles cumulating, and the SLIPSs TENG output performances increased with the thinner PFPE thickness. Both the triboelectrification behavior of hydrophobic/SLIPSs TENG assembled in this work are dominated by the electron transfer. Thanks to the introduction of SLIPSs, the SLIPSs TENG exhibits superior stability and durability than the hydrophobic TENG. The investigation of hydrophobic/slippery substrate–water interfacial triboelectrification contributes to optimize the TENG performances, and expands the application in harsh environments including low temperature and high humidity on the ocean.

Slippery lubricant-infused surfaces exhibit excellent fog-harvesting capacities compared with superhydrophobic and superhydrophilic surfaces. However, lubricant depletion is typically unavoidable under dynamic conditions, and reinfused oil is generally needed to recover the fog-harvesting capacity. Herein, an effective strategy for delaying the depletion of lubricant to prolong the service life of fog harvesting is proposed. An ultrathin transparent lubricant self-replenishing slippery surface was fabricated via facile one-step solvent evaporation polymerization. The gel film of the lubricant self-replenishing slippery surface, which was embedded with oil microdroplets, was attached to glass slides via the phase separation and evaporation of tetrahydrofuran. The gel film GFs-150 (with oil content 150 wt% of aminopropyl-terminated polydimethyl siloxane (PDMS–NH₂)) exhibited superior slippery and fog-harvesting performance to other gel films. Furthermore, the slippery surfaces with the trait of oil secretion triggered by mechanical stress exhibited better fog-harvesting capabilities and longer service life than surfaces without the function of lubricant self-replenishment. The lubricant self-replenishing, ultrathin, and transparent slippery surfaces reported herein have considerable potential for applications involving narrow spaces, visualization, long service life, etc.