One-step fabrication of dual-network cellulose-based hydrogel sensors with high flexibility and conductivity under ZnCl₂ solvent method for flexible sensing properties

Flexible smart sensing materials are gaining tremendous momentum in wearable and bionic smart electronics. To satisfy the growing demand for sustainability and eco-friendliness, biomass-based hydrogel sensors for green and biologically safe wearable sensors have attracted significant attention. In this work, we have prepared MCC/PAA/AgNWs/CNTs hydrogel sensors with excellent conductive sensing properties by a simple physical blending method. The ZnCl₂ solvent system was used to dissolve the MCC, followed by introducing acrylic acid to polymerize under UV illumination. Subsequently, CNTs and AgNWs were introduced into the hydrogel network to obtain hydrogel with excellent conductive sensing and antibacterial properties. Here, the physical and chemical interactions between the components significantly improved the mechanical properties of the hydrogels, exhibiting good tensile strength (0.45 MPa), elongation at break (558 %) and adhesion properties. Hydrogel presented outstanding electrical conductivity and significantly elongation sensitive (GF = 4.73 when elongated 90-120 %). Additionally, the hydrogel was also found to have significant antimicrobial activity against both Escherichia coli and Staphylococcus aureus, and the antibacterial effect was almost 100 %. With high sensitivity, stability, and reproducibility, these hydrogel strain transducers can detect various human movements, including finger flexion, wrist movement, joint motion, and heartbeat.