Highly conductive, super-stretchable cellulose hydrogels with self-adhesive properties for flexible sensors

Ionic conductive hydrogels (ICHs) are promising substitutes for rigid metal conductors in flexible sensors. However, integrating high strength, self-adhesion, conductivity, and anti-freezing properties remains a critical issue. Herein, a facile strategy for fabricating a mechanically robust hydrogel with remarkable conductivity and consistent self-adhesion by combining carboxymethylcellulose (CMC) and acryloyloxyethyltrimethyl ammonium chloride (ATAC), 2-acrylamide-2-methylpropanesulfonic acid (AMPS) is reported. The resulting hydrogels demonstrated high ionic conductivity (8.2 S/m), excellent mechanical properties (tensile strength: 0.5 MPa; tensile strain: >1701 %), and strong self-adhesion (up to 10.39 kPa) owing to ionic interactions and hydrogen bonding. With a gauge factor of 2.15, the hydrogels exhibited sensitive electromechanical responses, enabling reliable detection of both large and subtle human motions. When assembled into a flexible strain sensor, it exhibited high sensitivity, facilitating the detection of both significant deformations and subtle human movements. This work provides valuable insights into the rational design of cellulose-based ICHs for advanced bioelectronic applications.