Anti-freezing, moisturizing, resilient and conductive organohydrogel for sensitive pressure sensors

Abstract

Conductive hydrogels have attracted significant attention in the area of wearable pressure sensors due to their mechanical flexibility, conductivity and self-healing capability. At subzero temperatures, water-based conductive hydrogels unavoidably lose their elasticity and conductivity which limits their practical usages at low temperatures. However, traditional conductive hydrogels are short of moisturizing and anti-freezing ability due to the limitation of pure water solvent, which greatly restricts their application in extreme environments. In this study, an anti-freezing and moisturizing conductive double network organohydrogel was prepared by incorporating thioctic acid (TA) with polyvinyl alcohol-borate (PVA-PB) in carbon nanotubes (CNTs) that were dispersed in water (H2O) and ethylene glycol (EG). The as-prepared PVA-B-TA-CNTs organohydrogel presented outstanding anti-freezing performance (−60 oC), long-term moisturizing property (30 days), excellent stability (400 cycles) and fascinating conductive sensitivity (S = 0.625 kPa−1). The occurrence of dynamic covalent disulfide bonds and noncovalent hydrogen bonds endow the conductive organohydrogels with brilliant remoldability and self-healing ability, which are significant for practical applications. These remarkable advantages make PVA-B-TA-CNTs organohydrogel to have enormous potential in the application of wearable and flexible pressure sensors, human-healthy monitor, and intelligence devices.