Well-Ordered Nanohybrids with Network Structure for Metamaterials

Natural materials achieve extraordinary performance through hierarchical architectures with balanced strength, toughness, and functionality. The dactyl club of the mantis shrimp demonstrates how topological effect transforms intrinsically brittle hydroxyapatite into a tough, energy-dissipative framework; while the starfish skeleton, composed of diamond-structured calcium carbonate with nanoscale struts, exemplifies the nanosized effect that enhances specific strength and energy absorption. Inspired by nature, our laboratory biomimicked their structural motifs to replicate well-ordered hydroxyapatite and calcium carbonate nanonetworks that behave as mechanical metamaterials, exhibiting geometry-governed cellular deformation with exceptional ductility and energy dissipation through deliberate structuring at the nanoscale. Self-assembly of degradable block copolymers provides a versatile bottom-up strategy to emulate such topological designs in synthetic systems. By taking advantage of selective degeneration of one constituted block in the self-assembled block copolymer, well-ordered nanoporous polymers with open-cell structures can be obtained; that can be utilized as templates for templated synthesis to fabricate nanonetwork inorganics. However, the formation of porous structures inevitably introduces voids, resulting in reduction on strength and modulus. To overcome this limitation, the interconnected voids can be infiltrated with ductile polymers via templated polymerization, giving polymer/inorganic nanohybrids with network textures, giving structural integration for the development of nanohybrids with superior modulus and strength as well as excellent toughness.