A flexible capacitive pressure sensor based on an electrospun polyimide nanofiber membrane

A flexible capacitive pressure sensor based on electrospun polyimide (PI) nanofiber membrane as a dielectric layer has been proposed to improve its performance including sensitivity, detection limit and response speed due to its loose structures. An electrospun PI nanofiber membrane, a commercial PI tape and a PDMS membrane as dielectric layer had been tested and diverse thicknesses of PI nanofiber membranes were explored to optimize the dielectric layer. The sensor with such a dielectric layer exhibited high sensitivity (2.204 kPa⁻¹ at 3.5–4.1 Pa), wide scale range (0–1.388 MPa), low detection limit (3.5 Pa) and good cyclic stability (>10,000 cycles). A typical 4 × 4 sensor array could not only accurately sense corresponding force, but also identify the slide of force by monitoring dynamic capacitive changes of elements.