Superhydrophobic elastomer with leaf-spring microstructure made from natural wood without any modification chemicals

Herein, we report a superhydrophobic elastomer which was made directly from natural wood with a simple chemicothermal treatment without adding any modification chemicals. One of the most important findings is that the unique micro-nano structure in original wood was well maintained in the final wood elastomer, which result in many unique physical–chemical properties. The chemicothermal process tailors the nano-microstructure of wood by deteriorating polysaccharides into cellulose nanoarrays, and simultaneously, removes the hydrophilic groups in lignin which then re-assembles to cellulose nanoarrays to form a superhydrophobic surface with a contact angle up to 152°. Retained lignin aromatic skeleton also results in significant self-photothermal effect. Meanwhile, ray tissues in natural wood are hollowed to leave leaf-spring-like microstructure, which leads to great elasticity of wood elastomer with 97% stress retention at 60% strain after 103 compression cycles. Thanks to the microstructure and functions arising from wood itself, the elastomer shows many potential applications such as in solar-assisted crude oil recovery as well as water/oily liquids separation.