Highly stretchable, healable, sensitive double-network conductive hydrogel for wearable sensor

Hydrogel-based strain sensor with the stretchable, self-healable and wearable properties has made great contributions in the field of modern electronics. However, currently, ultra-high stretchability and strain sensitivity are required to satisfy the practical applications for polyvinyl alcohol-borate (PVA-Borax) hydrogel-based strain sensor. Herein, we fabricated a new highly stretchable hydrogel strain sensor based on PVA-Borax and (±)-α-Thioctic acid-iron (III) (TA-Fe³⁺) double-network hydrogel matrix and multi-walled carbon nanotubes (CNTs). The strain sensors displayed an extremely wide strain-sensing range (≈1350% fracture strain) with a gauge factor of 11.50 and showed rapid recovery of electrical properties in the cut-healing cycles (<4s). Compared with previous PVA-Borax based strain sensors materials, the new double-network hydrogel strain sensors achieved more favorable functionalities in human motion monitoring, which can satisfy versatile application requirements ranging from extremely stretchable, wearable, self-healable electronic devices to future soft robot.