Microwave puffing synergized with deep eutectic solvent induces a wrinkled cellulose wall architecture: A new strategy for elastic and conductive wood-based piezoresistive sensors.

Renewable elastic wood holds great potential to replace petroleum-based elastomers and supports a low-carbon circular economy, yet current research has remained largely focused on specific tree species, such as balsa, while fast-growing domestic species have been largely unexplored. Here, this study demonstrated a green and efficient strategy for preparing elastic and conductive wood using fast-growing Paulownia, through microwave puffing-assisted deep eutectic solvents (DES) treatment. Compared to conventional delignification methods, which mostly require at least 12 h and use corrosive chemicals, our synergistic approach reduced processing time to less than 7 h while employing biodegradable and recyclable deep eutectic solvents. After incorporation of polyvinyl alcohol and sodium chloride, the resulting wood composite retained 91% of its height after 50 compression cycles and the ionic conductivity reached 5.11 mS/cm, which was approximately 40 times higher than that of natural wood (0.13 mS/cm). As a piezoresistive sensor, it exhibited a high gauge factor of 33.77 within the strain range of 6.25% to 8.75%, enabling accurate detection of subtle human movements such as finger and wrist flexion, and demonstrating sensitive response to minute strains. This synergistic pretreatment not only efficiently overcomes mass transfer barriers in lignocellulose but also expands the raw material base for elastic wood production, offering a new, green, and efficient approach to developing high-performance elastic wood for soft and renewable devices.