High sensitivity, broad linearity range and low detection limit flexible pressure sensors based on irregular surface microstructure

Abstract

Flexible pressure sensors have attracted great interest due to their application potential in healthcare monitoring, electronic-skin and human-machine interfaces. To satisfy the requirements from practical applications, the sensors with high sensitivity, broad linearity range and low detection limit are urgently desired. Here, flexible pressure sensors with the negative replica (N-Sensor) and the positive one (P-Sensor) of the irregular surface microstructures are systemically investigated to achieve high performances. As revealed by the in situ observation method, the positive replica which mainly contained convex microstructures exhibits smaller initial contact area and could be compressed more easily than the negative one with porous surface. Therefore, the performances of the P-Sensor including sensitivity, linearity range and detection limit are greatly improved. The P-Sensor exhibits high sensitivity of 163.4 kPa −1 over a broad linearity range of 0–140 kPa, low detection limit of 1.3 Pa, fast response time (<10 ms) and good stability (>8000 cycles), which is one of the best results for flexible pressure sensors. Attributed to these excellent performances, the P-Sensor well performs in the measurements of human pulse, tactility and plantar pressure, showing great application potentials in human daily life. • Using negative and positive replicas of irregular microstructures manipulate the performance of flexible pressure sensors. • The sensors with positive replica achieve high sensitivity over a broad linearity range. • The flexible pressure sensors show great application potentials in human daily life.