Highly sensitive and flexible piezoresistive sensor based on MXene/LM@PDMS sponge for sedentary healthcare monitoring

Abstract

Flexible sensors with high sensitivity and wide detection range are highly desirable for applications in wearable devices, biomimetic robotics and human-machine interaction, etc. Herein, a 3D spongy structure based MXene/LM@PDMS composite using rigid MXene and liquid metal (LM) as hybrid conductive fillers was prepared by a facile salt template-dipping method. The incorporation of MXene/LM hybrid fillers results in the as-prepared MXene/LM@PDMS sponge with good flexibility and reliable compression properties. The MXene/LM@PDMS sponge-based (MXLP) pressure sensor displayed a wide sensing range (0−150 kPa), high sensitivity (334.1 kPa⁻¹), rapid response/recovery speed (0.29 s and 0.20 s, respectively), and long-term durability in pressure sensing. Furthermore, a large-area MXLP sensor array was fabricated to develop an intelligent cushion for sitting posture recognition. Assisted by a deep-learning algorithm based on convolutional neural networks (CNN), five representative sitting postures were recognized with a high accuracy of 99.4%, demonstrating great potential for applications in smart wearable devices and healthcare monitoring systems.