Dual Ion Regulated Eutectogels with High Elasticity and Adhesive Strength for Accurate Strain Sensors

Abstract

Eutectogels have attracted increasing attention from researchers due to their broad application potential, good environmental stability, biocompatibility, and low cost. Currently reported eutectogels generally show large residue strain and hysteresis, which will cause output signal inconsistency between the loading and unloading processes and is not conducive to accurate strain monitoring. Besides, the low adhesiveness of available eutectogels brings about difficulties in the installation of the sensors and dynamic interfacial stability between the sensors and human skin. Herein, a dual ion regulation strategy is proposed to obtain eutectogels with high resilience, high adhesiveness, ultralow residue strain, wide temperature adaptability (−20–60 °C) and good environmental stability. Strain sensors based on gradient eutectogels exhibit high sensitivity, a wide linear response range, and good cycling stability. The response curve shows negligible electrical hysteresis, providing consistent output signals at the fixed strain regardless of stretch or release. Accurate micrometry with a step as minute as 50 µm is realized. Moreover, the sensors demonstrate higher signal intensity and stability in human physiological signals and motion detection due to the strong interfacial bonding.