A Robust and Lubricating Hydrogel through a High‐Energy‐Storage and Low‐Dissipative Network Design

Abstract

ABSTRACT Hydrogels are promising joint‐lubrication materials because of their similarity to cartilage. However, most tough hydrogels rely on sacrificial bonds or dissipative networks to improve mechanical strength. These mechanisms inevitably introduce additional bulk energy dissipation during friction, compromising low‐friction performance. Here, a low‐dissipation network design strategy is proposed that combines a high‐energy‐storage bulk matrix with a surface energy‐release lubricating layer. Through sequential swelling and polymerization, a high‐energy‐storage network with hierarchically stretched chains is constructed. The optimized network shows significantly increased modulus and energy‐storage density while maintaining ultralow hysteresis. After surface dissociation on this high‐energy matrix, high‐energy hydrated chains are released and crowded at the surface and spontaneously form a self‐organized Voronoi‐like porous structure. This structured surface provides highly hydrated chains, strong entropic repulsion, and continuous water‐transport pathways, thereby reducing interfacial shear dissipation. Compared with conventional hydrogels, the resulting hydrogel maintains low friction over a wide load range and exhibits excellent fatigue and wear resistance. This work provides a high‐energy‐storage and low‐dissipation network design strategy and offers a promising approach for producing robust and lubricating hydrogels.