Highly conductive and adhesive wearable sensors based on PVA/PAM/SF/PEDOT:PSS double network hydrogels

In recent years, hydrogels had a wide range of applications in wearable devices, human health monitoring, or implantable sensors because of their good properties such as stretchability, conductivity, frost resistance, and transparency. However, the simultaneous integration of excellent mechanical properties and high electrical conductivity in a hydrogel sample still needs to be improved. In this work, silk fibroin (SF) and poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) were introduced into a poly(vinyl alcohol)/poly(acrylic amide) (PVA/PAM) double-network hydrogel to prepare PVA/PAM/SF/PEDOT:PSS hydrogel electrolytes via a one-pot method. Adding SF also enhances the mechanical properties of the hydrogel, making it three times stronger than the PVA/PAM double-network hydrogel. The hydrogel is versatile, with a strain range of 1–300%, making it an ideal resistive sensor for monitoring body pressure. More importantly, due to the hydrogel’s adhesion strength of approximately 665.8 kPa, the hydrogel can adhere to other surfaces during the detection process, significantly reducing the signal loss due to insufficient adhesion. In addition, the hydrogel also exhibits excellent electrical conductivity, can sensitively detect human limb movement, and can be applied to flexible electronic products such as electronic skin and soft robots.