Multiscale integral synchronous assembly of cuttlebone-inspired structural materials by predesigned hydrogels

The overall structural integrity plays a vital role in the unique performance of living organisms, but the integral synchronous preparation of different multiscale architectures remains challenging. Inspired by the cuttlebone's rigid cavity-wall structure with excellent energy absorption, we develop a robust hierarchical predesigned hydrogel assembly strategy to integrally synchronously assemble multiple organic and inorganic micro-nano building blocks to different structures. The two types of predesigned hydrogels, combined with hydrogen, covalent bonding, and electrostatic interactions, are layer-by-layer assembled into brick-and-mortar structures and close-packed rigid micro hollow structures in a cuttlebone-inspired structural material, respectively. The cuttlebone-inspired structural materials gain crack growth resistance, high strength, and energy absorption characteristics beyond typical energy-absorbing materials with similar densities. This hierarchical hydrogel integral synchronous assembly strategy is promising for the integrated fabrication guidance of bioinspired structural materials with multiple different micro-nano architectures. For bioinspired structural materials, integral preparation of multiscale structures remains challenging. The authors report a hierarchical strategy to assemble multiple micro-nano units to complex multiscale structures integrally synchronously.