Low temperature tolerant, ultrasensitive strain sensors based on self-healing hydrogel for self-monitor of human motion

Abstract

Self-healing hydrogel is attracting growing interest in the field of flexible sensor. However, the inevitably freeze at subzero temperature of conventional self-healing hydrogel significantly limits their further application. A low-temperature tolerance, toughness, conductive, and self-healing hydrogel using water and ethylene glycol as the binary solvent and dynamic supramolecular cross-linking among the carboxyl-decorated reduced graphene oxide (rGO), polyvinyl alcohol and borax is reported here. Owing to the multiple reversible bonds, the hydrogel exhibits excellent self-healing ability (100% in 5 min) at room temperature without any external stimuli. Additionally, the low-temperature tolerance hydrogel can be employed as resistance strain sensor to detect both large and tiny scale motions, which exhibits higher sensitivity (3.26–4.20) than that of conventional metal (2.0) in the temperature range of −10 to 60 °C. The sensor with ability of monitoring multifarious human motions can provide potential applications in healthcare monitoring and human-computer interaction.