Ultra-sensitive and electrical-mechanical dual self-healing ionic hydrogel-based wearable sensor for human motion detection

Hydrogel is an ideal choice as wearable sensors for human motion detection. However, low electrical sensitivity, narrow strain detection range and lack of self-healing performance still limit the further application and service life of hydrogel sensors. Herein, we report a self-healing ionic hydrogel based on copolymers of acrylic acid (AA) and acrylamide (AM), in which Fe3+ and tetramethylammonium chloride (TMAC) can bind with carboxylate through complex crosslinking and electrostatic interaction, respectively. Attribute to its supramolecular forces (including electrostatic interactions, hydrogen bonds) and complex cross-linking structure, the stretchable hydrogel has electrical-mechanical dual self-healing properties, that possess excellent mechanical properties (tensile strength at ∼320 kPa and strain at break ∼1600%), dual self-healing ability (∼87.5% self-healing efficiency in mechanical and instantaneous self-healing in electrical), ultra-high electrical sensitivity (GF = 18.26), and an extensive monitoring range (0.1–300% in strain and 8.15–31.56 kPa in pressure). This hydrogel shows great potential in wearable sensors for human motion detection.