Ultra-sensitive flexible piezoresistive pressure sensor prepared by laser-assisted copper template for health monitoring

The flexible sensors with microstructures have attracted much attention due to their ultrahigh sensitivity. To develop a controllable method for large-scale preparation of microstructures is the key to promoting the application of the flexible sensors. Herein, combining the laser processing technology with a copper template commonly used in roll-to-roll process, ultra-sensitive flexible piezoresistive pressure sensors with carbon nanotubes (CNTs) conductive layers on the ridge-shaped microstructures were fabricated and the effects of structure parameters on the performance of the sensors were systematically studied. Experimental results showed that the sensitivity of the sensors is positively correlated with the height h and spacing d of the ridge-shaped microstructure which are determined by laser processing parameters. The sensitivity of the sensor with the ridge-shaped microstructure (h=150 mu m, d=20 0 mu m) is as high as 1150.9 kPa(-1) at an applied pressure 50 Pa. Meanwhile, the sensor shows excellent stability ( 2000 cycles), rapid response time (43 ms) and recovery time (15 ms). Besides, the sensor was used to detect human physiological signals such as speaking, cheek bugling and artery pulse. These results indicate that combining the laser processing with copper templates has great potential in the controllable and large-scale fabrication of flexible sensors with microstructures for health monitoring. (C) 2021 Published by Elsevier B.V.