Stretchable and tough tannic acid-modified graphene oxide/ polyvinyl alcohol conductive hydrogels for strain and pressure sensors

With the rise of new fields such as wearable devices, human health monitoring, and artificial intelligence, flexible sensors have received extensive attention. Conductive hydrogels combine conductive fillers with the excellent properties of hydrogels, making them ideal materials for building flexible sensors. However, conductive hydrogels suffer from poor mechanical properties and low sensitivity, and designing hydrogels with high electrical conductivity and excellent mechanical properties remains a challenge. In this work, a conductive TA-RGO/PVA hydrogel was developed by incorporating TA-RGO nanocomposites into a PVA matrix. The prepared TA-RGO/PVA hydrogel exhibited excellent electrical conductivity, good elastic strain, and excellent mechanical stress. TA-RGO/PVA hydrogels can be used for stretchable strain and pressure sensors. The strain sensor based on the TA-RGO/PVA hydrogel exhibits excellent tensile strain sensitivity (1.936 78 gage factor in the 1%–280% strain region) with excellent stability. The sensor also maintains high sensitivity when used as a pressure sensor (2.2695 kPa−1 in the 0–9 kPa pressure range). These characteristics offer the TA-RGO/PVA hydrogel great potential in the application of wearable flexible strain/pressure sensors and bioelectrodes.