Super-stable modified wood for enhanced autonomous indoor humidity regulation

The crucial development of materials that automatically adjust indoor humidity, a significant factor in human health and daily life, has gained importance due to the emphasis on energy conservation. Wood, with its natural hygroscopic properties, is effective in this regard but faces challenges of deformation and cracking due to moisture content changes. Herein, we introduced an innovative in-situ wood modification strategy, which integrated deep eutectic solvent (DES) impregnation with heat treatment, producing dimensionally super-stable modified wood for enhanced autonomous indoor humidity regulation. This modification process focused on creating more robust cross-linking structures within the amorphous regions of the wood cell wall. As a result, water-induced deformation of natural wood was significantly reduced, as evidenced by an anti-swelling efficiency exceeding 80%, ensuring the long-term reliability of DES-modified wood in varying humidity environments. Additionally, the introduction of additional pores and hygroscopic sites in the cell wall enhanced the natural wood's moisture buffering value by 2.5 times, showcasing the superior ability of DES-modified wood to control indoor humidity effectively. Moreover, the DES-modified wood also exhibited commendable flame retardancy and antibacterial properties. Consequently, this novel modified wood emerges as a reliable material for indoor humidity regulation, promoting healthier indoor conditions and offering a sustainable alternative for energy-efficient construction practices.