Highly stretchable ionic conducting hydrogels for strain/tactile sensors

Ionic conductors based on stretchable hydrogels are on the rise to develop wearable devices because of choosing the same signal carriers for biological areas and intrinsic stretchability. In this paper, we demonstrate ionic strain/tactile sensors based on poly(acrylamide)/poly(ethylene oxide)/LiCl hydrogel. Owing to their chemically crosslinked structures and multiple H-bonding networks, these hydrogels exhibit excellent mechanical properties, such as high stretchability (∼8.8 times, 100 mm/min), high compression strength (556.58 MPa), high stab-resistant and damage-resistant ability and nearly ∼100% electrical self-healing ability. The use of salts (LiCl) as conductive ions makes the hydrogels ideal ionic conductors, imparting an ionic conductivity of ∼8 S/m. The ionic conducting hydrogels were demonstrated as strain/tactile sensors with high sensitivity to monitor human activity and external pressure. These hydrogel-based ionic sensors may find applications in sports monitoring, human/machine interfaces and soft robotics.