Flexible piezoresistive sensors with high sensitivity and ultra-wide pressure range based on alkalized MXene

Flexible pressure sensors, characterized by the high sensitivity and broad detection range, have gathered significant interest for applications in wearable electronics and human-machine interfaces. Despite their potential, the development of such sensors remains a formidable challenge. In this study, we report the fabrication of a flexible, highly sensitive piezoresistive sensor featuring a pleated architecture. This sensor was crafted from thermoplastic polyurethane (TPU) as the base material and a spun film serving as the flexible substrate, utilizing an electrospinning technique. The integration of MXene, which was subjected to structural optimization via alkaline treatment with sodium hydroxide (NaOH), was achieved through an impregnation and coating process onto the TPU film. The resulting MXene-composite sensor exhibits remarkable sensitivity (2.88 kP- 1), an extensive detection range (up to 300 kPa), rapid response time (100 ms), and superior stability over more than 5000 cycles. The sensor's versatility is demonstrated through its successful deployment in capturing a variety of physiological signals from the human body, such as pulse, respiration, and swallowing, as well as in monitoring full-body motion in real-time, including movements of the fingers, wrist, and sole of the foot. Furthermore, its application as a component of flexible electronic skin underscores its immense potential for integration into physiological analysis systems, humanoid robotics, and biomedical prosthetics.