Cellulose nanocrystal-modified hydrogel wearable sensor with self-healing function from dynamic bond and controllable dual hydrogen-bond crosslinking

Multi‑hydrogen bond networks have been introduced into hydrogels to enhance responsiveness, self-healing, and processability, but low interaction density and weak bond force limit their strength and tear resistance. In this study, we construct a multiple-crosslinked interpenetrating network system of dynamic covalent bond, dual‑hydrogen bond, and percolation around cellulose nanocrystals (CNCs) to resolve the function-plasticity trade-off. This design enhances strength and toughness without sacrificing the hydrogel's electromechanical sensing and self-healing performance. The resulting hydrogel demonstrates improved tensile strength (25.54 kPa), toughness (246.09 kJ/m 3 ), and self-healing (93.3 %). Meanwhile, based on ionic conductivity and excellent mechanical plasticity, the hydrogels achieve quick linear response sensing under a wide strain region and high sensitivity (4.36). The mechanism study for the multiple-crosslinked interpenetrating network system reveals that although dual‑hydrogen bonds are weak, they dissipate impact energy over long distances, reducing stress concentration. The percolation network, enabled by the rod-like filler particles of CNCs, enhances strength at a low filler concentration, allowing the dynamic covalent bond crosslinking to maintain flexibility and function. Since the CNCs also present high biocompatibility, the hydrogel must be able to offer promising solutions for applications in wearable electronics and wound dressings.