A Highly Stable and Durable Capacitive Strain Sensor Based on Dynamically Super‐Tough Hydro/Organo‐Gels

Abstract Capacitive‐type strain sensors based on hydrogel ionic conductors have undergone rapid development benefited from their robust structure, drift‐free sensing, higher sensitivity, and precision. However, the unsatisfactory electro‐mechanical stability of the conventional hydrogel conductors, which are normally vulnerable to large deformation and severe mechanical impacts, remains a challenge. In addition, there is not enough research regarding the adhesiveness and mechanical properties of the dielectric layer, which is also critical for the mechanical adaptability of the whole device. Here, a dynamically super‐tough capacitive‐type strain sensor based on energy‐dissipative dual‐crosslinked hydrogel conductors and an organogel dielectric with high adhesive strength is developed. Combining with the mechanical advantages of the hydro/organo‐gels, the capacitive strain sensor exhibits high stretchability and superior linear dependence of sensitivity with a gauge factor of ≈0.8% at 100% strain. Moreover, the sensor displayed ultrastability against various severe mechanical stimuli that can even survive unprecedentedly from extremely catastrophic car run‐over by 20 times. With these synergistic mechanical advantages, the capacitive strain sensor is successfully applied as a highly‐reliable wearable sensing system to monitor diverse faint physiological signals and large‐range human motions.