Supra-biomimetic Impact-Resistant Composites via Harnessing Macro-Microscale Competition.

Natural biomaterials achieve exceptional mechanical performance through multi-level hierarchical architectures, yet replicating or surpassing such topological control and multiscale synergy in synthetic hydrogels remains challenging. A key obstacle is the often-overlooked macro-microscale competition mechanism, where macroscopic reinforcement can conflict with finer-scale energy-dissipation pathways. Here, we overcome this limitation by embedding a 3-dimensionally printed gradient-twisted plywood (GT) framework into a hierarchically anisotropic (HA) hydrogel matrix, creating a topologically controllable supra-biomimetic composite (GT-HA composite). A supra-biomimetic design strategy is employed to regulate the macro-microscale competition, wherein the GT framework is expressly designed to coordinate macroscale stress guidance and crack deflection with micrometer-, nanometer-, and molecular-scale dissipation pathways. This coordinated multiscale dissipation endows composites with superior impact resistance. The GT-HA composite attenuates up to 88% of impact force at a low velocity and achieves a compressive strength of 183.57 MPa at a large strain rate of around 4,000 s