Design of PDMS/CNT flexible pressure sensor based on double structure with the regulation of electrical properties

Introducing microstructure on the surface or porous structure inside of dielectric layer can improve the sensitivity and monitoring range of the flexible pressure sensor. However, developing pressure sensors with high sensitivity in the high-pressure range is challenging because of the trade-off between sensitivity and linearity of pressure. Here, we report a design approach based on the collaboration of double structure and electrical characteristics that can improve sensor sensitivity at high pressure. The surface microstructural and internal porous structure of the dielectric layer provide a more comprehensive deformation range for the sensor from a mechanical perspective. The effects of the conductive carbon nanotube (CNT) content between two structures on the overall electromechanical characteristics of the sensor were studied. This collaborative (structure and component) design can effectively increase the monitoring range of the sensor and accomplish "gear shifting" of the sensitivity by the non-uniform distribution of CNT in the structure. The optimized capacitive pressure sensor exhibits outstanding sensitivity over a wide monitoring range (1.17 kPa-1 in the 0-100 kPa, 0.49 kPa-1 in the 100-350 kPa, and 0.23 kPa-1 in the 350-1000 kPa), and fast response capability (30 ms). The pressure sensor has excellent integrated sensing performance in rubber wheels' static/dynamic pressure monitoring, demonstrating application potential in high-pressure fields.