Lego Assembly-Inspired Self-Healing Hydrogels via Lignin-Mediated Multi-Dynamic Cross-linking and Slide-Ring Structure for Adaptive Sensors

Inspired by Lego assembly principles, we report a lignin-mediated multifunctional hydrogel (LPA-HPR 1%) engineered through synergistic multi-dynamic cross-linking and slide-ring topological control. This system integrates sodium ligninsulfonate-grafted-β-cyclodextrin (LS-CD) as a supramolecular hub with multi-dynamic motifs: hydrogen bonds, Fe3+ coordination bonds, and host–guest complexes, combined with hydroxypropyl polyrotaxane-grafted-vinyl cross-linker (HPR). The LS-CD nodes establish a hierarchical network through reversible host–guest interactions and metal coordination bonds, enabling autonomous healing (self-healing efficiency >99%) while maintaining structural integrity. The sliding rings of HPR synergize with the dynamic LS-CD network to achieve unprecedented mechanical tunability─combining high strength (114.96 kPa tensile strength, 10.01 MPa compressive strength), rapid energy recovery (98.79% recovery after 10 min) and fatigue resistance. Notably, the hydrogels can be flexibly assembled into various 3D configurations, like Lego bricks, from the macroscopic to the molecular level. The derived LPA-HPR 1% hydrogel sensors demonstrate exceptional strain sensing capabilities (GFmax = 5.94, 250 ms response) for monitoring subtle physiological motions (finger joint bending, wrist bending). This work establishes a sustainable paradigm for designing reconfigurable soft materials through biomass-derived dynamic chemistry and topological engineering, addressing critical needs in customizable wearable electronics and adaptive biomedical systems.