A tough hydrogel with fast self-healing and adhesive performance for wearable sensors

The purpose of this work is to address the two existing challenges. One is to achieve the balance of mechanical properties, adhesion, and self-healing ability in hydrogel used in wearable devices. The other is to use mature products as raw materials and simplify the preparation process of adhesive hydrogels, so as to make it possible for large-scale industrial production. A novel PAA/Fe/PVP hydrogel has been prepared by a simple one-step radical polymerization to meet the above requirements. As the main component of adhesives in daily life, PVP is used to improve the adhesion of the hydrogel. The adhesion as high as 64 kPa is achieved in the hydrogel. The adhesion can also withstand multiple uses due to the good mechanical properties of the hydrogel. Furthermore, the hydrogel displays outstanding self-healing ability in terms of both mechanical properties and conductivity. Because of the good mechanical properties, robust adhesion and rapid self-healing ability, the hydrogel-based sensors have demonstrated stability, accuracy and reliability in real-time monitoring of subtle facial micro-expressions and large human activities. In addition, the method uses mature products as raw materials, and the preparation process is simple, so it has the potential for large-area and low-cost production.