Highly Sensitive and Wide Linear Range Flexible Pressure Sensors with Hierarchical Microstructure and Its Application in Human Signal Detection

Flexible piezoresistive pressure sensors have been widely investigated for their potential applications in wearable medical devices. However, the low sensitivity and low detection range severely hamper their prospects in the above applications. In this paper, a flexible pressure sensor with high sensitivity and wide linear range was prepared using hierarchical microstructure carbon nanotubes/PDMS composite. The sensors’ preparation, pressure sensing mechanism, and sensing performance were investigated. The results show that the pressure sensor has a high sensitivity ($12.3 \mathrm{kPa}^{-1}$), a wide linear sensing range ($0-200 \mathrm{kPa}$), a fast response recovery time (83 ms), and a low minimum limit of detection ($\mathbf{5 0} \mathbf{~ P a}$). Application demonstrations of pulse monitoring show that the sensor is expected to be used in areas such as human medical and health detection.