Self-adhesive electronic skin for ultra-sensitive healthcare monitoring

Abstract

Due to their excellent mechanical properties and high tensile strain sensitivity, conductive hydrogels show great potential applications in the fields of artificial intelligence and human–machine interaction. The integration of reliable resilience, excellent viscosity and high strain sensitivity is a great challenge for conductive hydrogels. Here, inspired by human skin with a layered structure, glycerol was first introduced into a dual-network structure to prepare a hydrogel with hydrogen bonds, endowing the hydrogels with high resilience and adhesion. A mixture of graphene oxide and carbon nanotubes was sprayed on the hydrogel as a conductive layer to achieve high strain sensing. Then, a hydrogel with good toughness and high resilience was prepared by in situ polymerization as an elastic layer. Benefitting from its unique crack response mechanism, the integrated sensor showed high sensitivity (gauge factor = 20). Additionally, it presented a wide strain range (0–300%), super adhesion (56.9 N m⁻¹) to pigskin with similar elastic modulus to the human body, and low hysteresis. This study provides a feasible solution for the improvement of wearable electronic devices for healthcare monitoring.