Wearable MXene nanocomposites-based strain sensor with tile-like stacked hierarchical microstructure for broad-range ultrasensitive sensing

Flexible wearable strain sensors with high sensitivity, broad sensing range, large stretchability and low strain detectability have drawn tremendous interest for various applications in electronic skins, human motion detection, and medical diagnosis. However, conventional strain sensors usually showed narrow sensing range, low sensitivity, and complicated fabrication process, which restrict their potential applications in precise detection of vital healthcare signals. In this work, we report the fabrication of a flexible wearable strain sensor by using the MXene/polyaniline fiber (PANIF) (MXene/PANIF) nanocomposites sensing layer with tile-like stacked hierarchical microstructures, inspired from the overlapped rooftop tiles of the ancient palace. The MXene/PANIF nanocomposites sensing layer with tile-like stacked hierarchical microstructures is prepared via spreading MXene and PANIF layer on the elastic rubber substrate respectively. The assembled strain sensor can be used to detect broad-range (up to 80% strain) human motion with ultralow detection limit (0.1538% strain), high sensitivity (up to 2369.1 for the gauge factor (GF)), and excellent reproducibility and stability. Furthermore, the strain sensor could be coupled to a wireless transmitter for wirelessly human motion monitoring. Therefore, the wearable MXene nanocomposites-based strain sensor is a promising and attractive future electronic device for various real-time human motion detection, personal healthcare monitoring, and clinical diagnosis.