A “special Sandwich” Structured Hydrogel-Based Sensor with Excellent Environmental Stability and Controllable Sensitivity

Today, hydrogel-based flexible sensors have drawn tremendous attention in many fields. However, the hydrogel-based sensors suffer from poor stability and low sensitivity which severely limits their further development. It is still “a black box” to understand the encapsulating effect as well as wire connection method on the performance of the hydrogel-based sensors. To address these problems, we proposed a rational encapsulation model which fully encapsulate the hydrogel into Ecoflex. Owing to the excellent barrier property of Ecoflex, the encapsulated sensor can preserve 98.1% after storing for one month. Moreover, the response time of the assembled sensor was also three times shorter than that before encapsulation. In addition, we also performed the theoretical analysis and simulation on the contacting area between the hydrogel and the conducting wires. It was surprised to find that the contacting area plays a significant effect on the sensitivity of the hydrogel sensors, which implying that reasonable design of encapsulation and connection method are also indispensable parts for the fabrication of the successful hydrogel sensors. Therefore, we paved a novel insight to optimize the property of the hydrogel sensors, which is greatly favorable for the development of the hydrogel-based sensors to be applied various fields.