Fabrication of High-Strength and High-Toughness Holocellulose Materials via Spider Silk-Inspired Biomimetic Mechanisms

The development of high-strength and high-toughness wood-based composites remains a crucial but challenging goal in industrial applications, as these two properties are often mutually exclusive in traditional material design. Inspired by the multiscale structure of spider silk rigid β-sheet crystals and dynamic amorphous matrix, we propose a biomimetic holocellulose material (HEODW) with a dynamic covalent network. Through the selective oxidation of cellulose and the Schiff base reaction with ethylenediamine, a dynamic imine bond network was constructed in the wood cell wall. The network can undergo reversible fractures and recombination in the stress concentration area and achieve efficient energy dissipation through finite molecular slip. HEODW exhibits excellent mechanical properties: a tensile strength of 479.51 MPa, a Young’s modulus of 17.61 GPa, and a toughness of 14.85 MJ/m3, which are 6.3 times, 4.6 times, and 15.7 times higher than those of natural wood, respectively. The flexural strength and flexural modulus reached 216.49 MPa and 23.02 GPa, respectively. In addition, the chemical vapor deposition organic silane modification gives the material persistent hydrophobicity, expanding its application in humid environments. This study demonstrates a feasible spider silk-like strategy that can break through the trade-off between the strength and toughness of holocellulose materials and provide a sustainable path for the development of high-performance structural wood composites.