High strength, self‐healing, and anti‐freezing polyurethane ionogel based on multiple hydrogen bonding for wearable strain sensor

Abstract Hydrogel‐based electronic skin sensors often suffer from low mechanical properties, poor durability, and low temperature resistance. Herein, an ionogel was fabricated by casting the water‐borne polyurethane (WPU) and 1‐ethyl‐3‐methylimidazoliumdicyanamide (EMIM:DCA). The imidazolidinyl urea with multiple hydrogen bonds as chain extenders was introduced into WPU systems. Owing to the multiple hydrogen bonds, the ionogels exhibited good mechanical properties with a tensile stress of 1.45–12.09 MPa, a strain of 730%–860%, and good resilience. Moreover, the mechanical properties, conductivity, and sensing ability of the ionogels could be conveniently healed with the assistance of heat. EMIM:DCA endowed the ionogels with excellent ionic conductivity at room temperature (1.8–246 μS cm −1 ). In addition, due to the low vapor pressure of EMIM:DCA, the ionogel exhibited excellent anti‐freezing property at −20°C. The ionogel can be assembled into a sensor to monitor the movements of human body with good responsiveness and stability.