Bamboo-node-inspired cellulose nanofiber-based conductive aerogel for motion monitoring.

Biomass-based conductive aerogels with excellent biocompatibility, high porosity, and facile functionalization are the key materials for new-generation sustainable high-performance piezoresistive sensors. However, the single lamellar structure of conventional aerogels and the inherent agglomeration tendency of conductive nanomaterials severely hamper the mechanical and strain sensing properties of biomass-based aerogels. Herein, inspired by the natural bamboo-node structure, a novel gelation-confinement strategy was developed to construct a unique bamboo-node-reinforced structure by incorporating metallogels (MOGs) and carbon nanotubes (CNTs) into cellulose nanofibers (CNFs). The resulting CNF-based aerogel exhibits excellent mechanical stability and can withstand over 5000 compression cycles at 50% strain. Meanwhile, integration of the aerogel into a flexible piezoresistive sensor endows the device with comprehensive strain sensing properties, including high linear sensitivity (S = 4.14 kPa-1 in the 0-2 kPa range; S = 1.88 kPa-1 in the 2-92 kPa range) and a low-pressure detection limit of 2.21 Pa. These multifunctional features endow the composite aerogel with great application potential in motion monitoring.