Chitosan-driven skin-attachable hydrogel sensors toward human motion and physiological signal monitoring.

Recently, flexible and wearable sensors assembled from conductive hydrogels have attracted widespread attention. However, it is still a great challenge to make hydrogels with sufficient mechanical properties, self-adhesiveness and strain sensitivity. Here, a strong, tough, and self-adhesive hydrogel is successfully fabricated by a one-pot method, which introducing chitosan and 2-acrylamido-2-methylpropane sulfonic acid into the polyacrylamide network. The hydrogels exhibited adhesion (the peel strength reaches 798 N/m), mechanical property (The breaking strength and strain can reach 111 kPa and 2839%) and electrical conductivity (conductivity up to 0.0848 S/cm), which are suitable for wearable epidermal sensors. Besides, the hydrogels also possessed transparency. Therefore, this work would provide a novel insight on the fabrication of multi-functional self-adhesive hydrogel sensors.