Supramolecular Semi-Convertible Hydrogel Enabled Self-healing Responsive Lubrication under Dynamic Shearing

Abstract The cartilage-inspired hydrogel has attracted great interests due to its tunable mechanic and low friction, however, it is incapable of self-healing under a complex dynamic shearing environment. In this contribution, a self-healing semi-convertible hydrogel is developed, which can recover the unique dynamic active lubricating function under shearing. Based on the cooperating strategy of noncovalent and covalent bonding, the prepared SHSCH composes of three interpenetrated networks including i) shear-responsive N-fluorenylmethoxycarbonyl-L-tryptophan supramolecular network, ii) self-healing polyhydroxyethyl acrylamide network and iii) rigid polyvinyl alcohol covalent network. Dynamic shear-responsive lubricating function is achieved due to the appearance of disassembled FT supramolecular sol layer on the surface triggered by shear force. This shear-responsive lubricating function and the mechanical property of prepared hydrogel can be self-healed under shearing environment through the noncovalent hydrogen bonding assembly of polyhydroxyethyl acrylamide associated by the π-π assembly of FT. The as-developed semi-convertible hydrogel exhibits unprecedent self-healing performance comparing with other materials reported. We demonstrated a proof-of-concept on the self-healing lubrication of simplified artificial abrasion cartilage under dynamic shearing condition. This study will offer a new strategy on designing the self-healing soft devices under dynamic stimuli far beyond the lubricating materials.