Tunable Fabrication of Flexible Resistive Pressure Sensors via Vapor-Induced Phase Separation for High Sensitivity and Wide Linear Detection Range

This paper presents the fabrication of a flexible resistive pressure sensor featuring high sensitivity and a wide linear detection range. The sensor consists of two opposing thin composite layers composed of multiwalled carbon nanotubes (MWCNTs) and polyvinylidene fluoride (PVDF), which serves as the sensing element. The sensing layer is formed via blade coating of MWCNT-PVDF slurry over a large area, followed by a drying process. By modulating the drying temperature, tunable sensitivity from 6.9 to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$26.7\ \text{kPa}^{-1}$</tex> and linear detection range spanning 3000 to 6900 kPa are achieved. This tunability is achieved through vapor-induced phase separation, which controls the surface roughness of the sensing layer without the need for complex micromachining or micro-molding processes. The scalability of the process is demonstrated through the fabrication of a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$10\times 10$</tex> grid-type sensor array for pressure mapping. Our process enables the development of high-performance flexible pressure sensors while allowing customizable tuning of their performance.