Tuning Network Topology through Polymerization-Induced Entanglements for Tough and Low-Hysteresis Double Network Hydrogels

In conventional double network (CDN) hydrogels, dense chemical cross-linking in the first network frequently induces structural imperfections, resulting in significant energy dissipation and substantial hysteresis under stress. To improve structural uniformity, spatial heterogeneities can be minimized by introducing mobile cross-linking, which facilitates the creation of a more homogeneous network. Herein, we employed a polymerization-induced entanglements (PIEs) strategy to tune the first network from a traditional net-like to a fabric-inspired topology, simultaneously promoting greater chain entanglement with the second network. This innovative approach enables PIEs DN hydrogels with exceptional performance, including significantly reduced hysteresis (0.15), high tensile strength (1.25 MPa), and excellent toughness (5800 J/m²), overcoming the long-standing trade-off between toughness and hysteresis observed in CDN hydrogels and offering insights and avenues for expanding DN hydrogel applications.