Highly Stretchable, Highly Sensitive, and Antibacterial Electrospun Nanofiber Strain Sensors with Low Detection Limit and Stable CNT/MXene/CNT Sandwich Conductive Layers for Human Motion Detection

With the rise of the concept of "Internet of Everything", the development of wearable sensing devices is growing rapidly. Among them, crack-based strain sensors have received much attention due to their high sensitivity. However, the application of crack-based strain sensors has been limited by the relatively narrow sensing range. Here, a sandwich structure of a CNT/MXene/CNT sensing layer was realized on the flexible thermoplastic polyurethane substrate prepared by electrospinning, followed by layer-by-layer vacuum filtration. The two stable carbon nanotube (CNT) layers broaden the sensing range, and the strain sensor exhibits excellent sensing range (390%) and stability (3000 tensile tests). The strain sensor also shows excellent sensitivity (GF = 2159.5), low detection limit (0.05%), and fast response time (∼50 ms). The sensor is responsive to different movements when being applied to human motion detection, and the smart wearable device based on the strain sensor shows excellent performance in gesture language recognition. In addition, the antibacterial property of the conductive material inherently facilitates the wider application of the strain sensors.