An all-natural fire-resistant bioinspired cellulose-based structural material by external force-induced assembly

Natural wood is a widely used structural building material because of its light weight and high strength, yet it is limited by the ignitability. Traditional top-down strategies can delay the burning time of wood-derived materials but hardly reach incombustible performance. Here, we develop a bottom-up external force-induced assembly strategy to fabricate nonburning nacre-mimetic structural materials based on the shear-thinning behavior of cellulose nanofibers, the main component of wood. The highly ordered brick-and-mortar structure endows the structural material with excellent comprehensive mechanical properties and oxygen insulation, giving it better specific flexural strength [143 MPa/(Mg m−3)] and limit oxygen index (100%) than various natural woods. Furthermore, the house model, made of bioinspired structural materials, does not burn or collapse even in a butane blowtorch flame (more than 1100 °C), demonstrating its great potential as a sustainable, lightweight, strong, and safe structural building material.