A ENR-based conductive film integrating electricity-triggered self-healing, damage detection and high sensitivity for flexible sensors

Abstract

Wearable flexible sensors cannot lock damage location in time for self-healing due to a lack of damage detecting capacity, which will indulge slight damages to grow up to cause irreparable losses. To address this issue, we design a conductive film based on epoxidized natural rubber (ENR), lipoic acid (LA) and carbon nanotubes (CNT), which has electricity-triggered self-healing and damage detection capabilities for applications in flexible sensors. Due to the excellent electrothermal effect (≈130 ℃ in 20 V) of CNT, the film achieves a 100 % self-healing efficiency under an applied voltage of 20 V for only 4 h. More importantly, the location of damage can be detected by the apparent color difference in the infrared thermogram caused by the different resistances between the damaged and undamaged areas under applied voltage. The film has an acceptable mechanical property of 3.36 MPa, excellent stretchability up to 479 %, and good conductivity of 0.77 S/m. Moreover, it shows high sensitivity (gauge factor up to 12.01) and good reliability (2000 cycles) in flexible sensing and can be used for human body operation detection and anti-counterfeiting. We believe that this functional film provides ideas for the development of a new generation of wearable flexible sensors integrating electricity-triggered self-healing and damage detection.