Stretchable and Sensitive Strain Sensors Based on CB/MWCNTs-TPU for Human Motion Capture and Health Monitoring

Flexible strain sensors have attracted significant attentioninthe wearable electronic device field, owing to their exceptional ductility,sensitivity, and durability compared to rigid strain sensors. However,the limited strain detection range or sensitivity has hindered theirwidespread application. In this study, a flexible strain sensor isfabricated by screen-printing a conductive carbon black ink layeron a conductive flexible composite layer made of thermoplastic polyurethaneand multiwalled carbon nanotubes. Both kirigami-patterned and fingerprint-patternedstructures are introduced to the architecture of sensors; while theformer is designed for the improvement of strain sensing range, thelatter serves for the enhancement of sensitivity and interfacial adhesion.It is demonstrated that the sensor achieves high sensitivity witha gauge factor of up to 5705.53 and has a wide strain sensing rangefrom 0 to 150%. Besides, the sensor also shows good durability (6000stretching-releasing cycles) and a fast response time of similar to 220ms. The excellent sensor performance of the flexible strain sensorsuggests promising applications in human-computer interaction,medical health monitoring, and motion capture.