Low coefficient of friction hydrogels with fast self-healing properties inspired by articular cartilage

Hydrogels have potential applications in artificial cartilage , soft robotics, and tissue engineering, owing to their excellent wettability , flexibility, and biocompatibility. However, poor lubrication and fragile mechanical properties often limit their applications. In nature, articular cartilage and cornea are coated by brush-like mucous to realize lubrication. Herein, we present a nature-inspired strategy for improving the lubrication properties of hydrogels. A model hydrogel is prepared using poly(vinyl alcohol), borax , and poly(ethylene oxide). The PEO forms a brush-like hydrophilic lubricating layer on the surface of the hydrogel. Thus, the PVA/Borax/PEO hydrogel exhibits a low coefficient of friction (0.08). In addition, after healing for 30 s in the air, the PVA/Borax/PEO hydrogel with a dynamic borate bond exhibit a 93 % cure in strength . Moreover, PVA/Borax/PEO hydrogels also exhibit excellent underwater self-healing ability. With the combination of lubrication and self-healing properties, the PVA/Borax/PEO hydrogels have great potential for use in a wide variety of fields.