Bioinspired fabrication of asymmetric wood materials for directional liquid manipulation and transport

Directional liquid transport, an essential process found in many natural creatures, is of great importance to environment, energy, and even life. Wood plants possess directional water transportation from soil to air, however, wood-based materials have no longer such performance because the pressure difference induced by transpiration is lost. Inspired by the controlled transport of water droplets on cactus pine, here, wettability gradient is constructed along wood channels, fabricating novel asymmetric wood slices. The hierarchically micro-/nano-structures and wettability gradients of the slices guarantee the tunable surface wettability and directional liquid transport property. Besides water, the resultant asymmetric wood can directionally deliver oils and moisture. Moreover, the functional wood displays high resistance against harsh corrosions without changing micro-structures or losing directional liquid transport property. The results demonstrate the asymmetric wood material will be useful in liquid manipulation, water harvest and treatment, self-cleaning, anti-fouling, and smart building materials.