Enhancing the Strength of Mineralized Wood via Cellulose Mineralization-Induced Contractile Stress

Natural wood is a sustainable material, but its engineering applications are often limited by flammability, biodegradation, and anisotropic mechanical behavior. Inspired from biomineralization─an inorganic/organic hybrid strategy found in nature, we develop an in situ mineralization approach to fabricate high-performance strontium carbonate (SrCO 3 ) mineralized wood. SrCO 3 precursors initially nucleate on the cellulose matrix and subsequently expand to fully mineralize the cell wall, a process during which the cellulose matrix induces a preferred orientation of the nanocrystals. Specifically, these nanocrystals become embedded within the cellulose matrix of the cell walls while preserving the intact lumen architecture, thereby achieving a high mineral content of 70 wt %. Furthermore, megapascal-level contractile stress is generated along the c -axis of cellulose crystallites during mineralization, resulting in a distinct expansion of the cellulose (200) plane spacing. This prestressed mineralized wood exhibits a tensile strength of 23.1 MPa, significantly higher than its annealed counterpart (11.3 MPa); concurrently, the mineralized wood composite achieves a flexural strength of 140.4 MPa, surpassing that of natural wood by 18-fold. Moreover, the mineralized wood demonstrates superior flame retardancy and resistance to fungal decay. This study elucidates the strengthening mechanism conferred by mineralization-induced contractile stress and presents a scalable pathway for fabricating robust artificial composites.