Beyond Cartilage-Inspired Supramolecular Polyurethane for Adaptive Impact-Resistant Protection with Robustness,...

Conventional ceramic and metallic impact-protective materials are strong yet brittle and heavy, whereas soft materials such as Sylgard 184 and Styrofoam provide limited energy absorption and structural resilience. Achieving high impact resistance together with intrinsic self-healing and recyclability remains a long-standing challenge for polymeric systems, as most high-strength soft elastomers rely on permanent covalent networks that hinder their reprocessability. Taking inspiration from human articular cartilage-a natural impact-dissipative yet non-healable tissue-we developed a supramolecular polyurethane-urea elastomer (PU-BAMB) that emulates its fibrous-matrix architecture by integrating hierarchical hydrogen bonding and π-π stacking interactions through an aromatic diamine chain extender. This molecular design reproduces the multilevel energy-dissipation mechanism of cartilage while overcoming its biological limitation by introducing intrinsic self-healing and recyclability. The cooperative supramolecular framework achieves a finely tuned synergy between elasticity and rigidity, resulting in remarkable tensile strength (21.08 MPa), high fracture energy (138.36 kJ m^{- 2}), and rapid self-healing (97% recovery within 1 h at 90°C). PU-BAMB exhibits pronounced hysteresis, strain-rate-induced stiffening, and outstanding impact-mitigation efficiency while retaining lightweight flexibility and sustainability. This work establishes a bio-inspired yet functionally advanced design paradigm for constructing robust, self-healing, and recyclable impact-resistant elastomers for next-generation protective coatings, damping systems, and adaptive wearable devices.