Interfacial self-healing lubrication in pen nib steel: Water-based composite nanoparticle lubricants for friction reduction

Friction and wear of pen nib steel in neutral ink systems is responsible for writing performance and service life. A water-based composite nanoparticle lubricant, (oleic acid-3-aminopropyltriethoxysilane-hyaluronic acid-titanium dioxide), named RNTH, was designed via a nuclear chain crosslinking method featured by shear-induced self-healing mechanisms in hydrogels. In comparison with traditional polyol lubricants, RNTH reduced the coefficient of friction by 17 %, wear mass loss by 28.3 %, and wear depth by 3–5 μm. Meanwhile, RNTH forms a dynamic lubrication layer at the friction interface, where the solid phase provides mechanical support and the liquid phase enables self-healing through hydrogen bond hydration, ensuring stable long-term lubrication. Importantly, this study introduces a biomimetic self-healing strategy to improve the durability of water-based lubricants under dynamic friction, offering new insights for designing high-precision liquid lubrication systems in industrial applications.