Tetradic double-network physical crosslinking hydrogels with synergistic high stretchable, self-healing, adhesive, and strain-sensitive properties

Herein, we demonstrate a tetradic double-network physical cross-linking hydrogel comprising of gelatin, polyacrylic acid, tannic acid, and aluminum chloride as wearable hydrogel sensors. Based on the coordination bonds, hydrogen bonds, and chain entanglements of the two networks, the acquired hydrogel possesses excellent tensile properties, self-healing performance, and adhesiveness to many substrates. Mechanical properties can be tuned with fracture strain ranging from 900 to 2200% and tensile strength ranging from 24 to 216 kPa, respectively. Besides, the hydrogel also exhibits good strain-sensitivity when monitoring the motions of humans, such as bending of fingers, bending of elbows. Hence, we can believe that the GATA hydrogel has numerous applications in soft robots, intelligent wearable devices, and human health supervision.