High electrical self-healing flexible strain sensor based on MWCNT- polydimethylsiloxane elastomer with high gauge factor and wide measurement range

Flexible strain sensors are widely used in wearable electronic devices, sports health detection and electronic skin. These sensors have the advantages of large strain range, full flexibility and biocompatibility. However, flexible strain sensors will inevitably suffer mechanical damage during operation, resulting in degraded sensor performance and shortened life. In this paper, a high electrical self-healing flexible strain sensor (ESFSS) based on multi-walled carbon nanotubes and polydimethylsiloxane (MWCNT-PDMS) elastomer is proposed. The ESFSS is designed by the modified self-healing PDMS elastomer (SPE) that gives the ESFSS electrical self-healing ability. Moreover, the conductive filler (MWCNT) is introduced to the sensor to endow the ESFSS with high sensitivity and a wide measurement range. The matrix materials of the ESFSS are characterized, the electrical healing mechanism and sensing mechanism of the ESFSS are analyzed and the high electrical self-healing performance of the ESFSS is demonstrated with an electrical healing efficiency (EFE) of 97.8%. In addition, the proposed ESFSS also has high gauge factor (GF) values of 57.894 (0–85.36%), 993.088 (85.36%–106.64%) and 5536.346 (106.64%–136.32%) and a wide measurement range (0–136.32%). The ESFSS has a promising application in human motion detection.