Effects of service condition on the performance of conductive polymer composites for flexible strain sensors

Flexible strain sensors based on conductive polymer composites (CPCs) are widely used in wearable electronics and electronic skin due to their simple preparation and outstanding performance. However, the performance like sensitivity and dynamical stability of flexible strain sensors is coupled with complex operational conditions, which prevents the sensors from large-scale practical applications. In this work, the effects of different loading rates and loading modes on the performance of the flexible strain sensor were systematically investigated. It was found that high loading rate can increase the sensitivity and the degree of hysteresis phenomenon (shoulder peak, spoon valley and drift), which is attributed to the viscoelasticity of polymer. Meanwhile, non-uniform loading mode has insignificant influence on the sensitivity and hysteresis of strain sensors in comparison to uniform loading mode. Moreover, the force-electric equivalent model was proposed to explain the causes of various hysteresis phenomena as well as the sensitivity mechanism affected by loading rate. Furthermore, a theoretical formula of the resistance of flexible strain sensor was presented and optimized to describe the relationship of variation of resistance against different loading rates. These presented results bring useful insights on the exploration of CPCs based strain sensors for wide applications under complex service conditions. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

This study systematically investigated the effects of different loading rates and loading modes on the performance of flexible strain sensors, revealing that high loading rates can increase sensitivity and the degree of hysteresis, and that non-uniform loading modes have a minimal impact on sensor performance compared to uniform loading modes.