Fabrication method and various application scenarios of flexible capacitive pressure sensor based on direct formation of conical structure

The utilization of the electrostatic spinning process has revolutionized the preparation of dielectric layers for conventional flexible capacitive pressure sensors (CPS), making it possible to prepare sensors with excellent performance that are both ultra-thin and flexible. The introduction of microstructures onto the electrostatically spun dielectric layer has been shown to significantly enhance sensor performance, with the templated method being the prevailing approach. However, this method is costly and prone to damaging the structures during film removal. In this study, we report a novel approach for producing a PVA/phosphoric acid electrostatically spun film with surface conical microstructures, eliminating the need for a template in the fabrication of flexible capacitive pressure sensors (APPS). The APPS with surface conical microstructure was prepared by simply adjusting the parameters of the electrostatic spinning process. Operating on the electric double layer (EDL) sensing mechanism, APPS demonstrated excellent performance. The device exhibited a low limit of detection (LOD) down to 1 Pa, a high sensitivity of 0.54 kPa-1 in the range of 0-70 kPa, and a stable performance over 1200 s load-unload cycle tests. These superior characteristics position the APPS for applications to monitor human physiological indicators and enhance human-computer interaction experiences.