Double cross-linked wood hydrogels with high anisotropy and ionic conductivity for sensitive pressure sensing.

The fabrication of cellulose hydrogels from nature-abundant wood through a top-down strategy has attracted extensive attention. However, simultaneous realization of superior mechanical strength and ionic conductivity is a huge challenge. Herein, highly anisotropic, flexible, and conductive wood hydrogels were prepared by a designed double cross-linked strategy. By integrating acrylamide/acrylic acid and Fe3+ ions into the delignified wood matrix, the mechanical performance and ionic conductivity can be largely enhanced. The optimal sample demonstrated a tensile fracture strength of 8.2 MPa along the tree growth direction, high conductivity of 0.040 S/m. The resulting hydrogels were assembled into sensors and used to monitor diverse human activities, and they could realize highly sensitive and durable human motion detection. This work provides a new direction for the design of wood-based human motion sensors. [Display omitted] [ABSTRACT FROM AUTHOR]