Drying constitutes an essential step in aerogel fabrication, where the drying method directly determines the pore structure and consequently influences the material’s functionality. This study employed various drying techniques to prepare balsa-wood-derived aerogels, systematically investigating their effects on microstructure, density, and performance characteristics. The results demonstrate that different drying methods regulate aerogels through distinct pore structure modifications. Supercritical CO₂ drying optimally preserves the native wood microstructure, yielding aerogels with superior thermal insulation performance. Freeze-drying induces the formation of ice crystals, which reconstructs the microstructure, resulting in aerogels with minimal density, significantly enhanced permeability, and exceptional cyclic water absorption capacity. Vacuum drying, oven drying, and natural drying all lead to significant deformation of the aerogel pore structure. Among them, oven drying increases the pore quantity of aerogels through volumetric contraction, thereby achieving the highest specific surface area. However, aerogels prepared by air drying have the highest density and the poorest thermal insulation performance. This study demonstrates that precise control of liquid surface tension during drying can effectively regulate both the pore architecture and functional performance of wood-derived aerogels. The findings offer fundamental insights into tailoring aerogel properties through optimized drying processes, providing valuable guidance for material design and application development.

The development of sustainable wood-based composites has driven increasing interest in formaldehyde-free, low-odor, and recyclable bonding systems. However, achieving high mechanical performance and dimensional stability in high-density fiberboards (HDFs) without synthetic adhesives remains a challenge. Here, we report a two-step strategy combining oxidative pretreatment of wood fibers with supramolecular assembly of tannic acid (TA) and sodium ions (Na⁺) to fabricate low-odor, recyclable HDF. Oxidation generated abundant carboxyl groups on the fiber surface, enabling strong coordination and hydrogen-bonding interactions between TA and Na⁺, which constructed robust inter-fiber supramolecular networks without formaldehyde-based adhesives. The resulting HDF exhibited excellent mechanical properties, with an internal bond strength of 3.1 MPa, a modulus of rupture of 49 MPa, and 24 h water thickness swelling of only 12%. Odor and VOC analysis revealed only trace benzene, demonstrating markedly low odor. Furthermore, the reversible nature of Na⁺-TA interactions allowed efficient fiber separation and recyclability under mild aqueous conditions. This oxidation-assisted supramolecular approach provides a sustainable route for producing high-performance, low-odor, and recyclable fiberboards, offering a viable alternative to conventional polymer-bonded wood composites.

Materials exhibiting a Poisson's ratio of zero have attracted considerable interest due to their unique properties and potential applications in various fields, including aerospace, athletic footwear, and sporting equipment. However, the high costs associated with their structural fabrication and the dependence on synthetic chemical materials for most zero Poisson's ratio materials complicate the preparation processes of current elastic materials, resulting in negative environmental impacts. This study presents a sustainable treatment strategy that utilizes the inherent cellular structure of wood to achieve a zero Poisson's ratio, thereby enhancing its elasticity. By strategically selecting tree species with varying tissue compositions and employing simple chemical and heat treatments, we developed a commercially viable elastic wood material with a zero Poisson's ratio that meets diverse stress rebound requirements. The unique internal structure of the wood not only provides high fatigue resistance-capable of withstanding 5000 cycles of compression at a strain of 40 %-but also ensures excellent resilience and processability. At a deformation level of 60 %, the elastic modulus reaches 90.9 MPa. Additionally, the material retains its elasticity even at extremely low temperatures of -196 °C and demonstrates the ability to endure elevated temperatures following carbonization at 1200 °C. This study demonstrates that wood-based materials with a zero Poisson's ratio exhibit remarkable stability after cyclic compression, presenting a viable pathway for developing superelastic materials suitable for both high- and low-temperature applications.