Flexible Wearable Iontronic Pressure Sensors Based on an Array of Semiellipsoids with Micropillars for Health and Motion Monitoring

Abstract

Flexible wearable pressure sensors are essential in human–machine interaction and health monitoring. Capacitive pressure sensors often employ microstructures or porous materials to enhance the compressibility of the dielectric layer, improving sensitivity and response speed. Here, we report a flexible iontronic pressure sensor fabricated with a 3D-printed mold, incorporating an ionic gel film with an array of semiellipsoids with micropillars. An electric double layer (EDL) forms at the upper and lower interfaces of the microstructure. As the pressure increases, the microstructure is gradually compressed, leading to an increase in the capacitance. The device exhibits a sensitivity of up to 3.19 kPa^–1 in the pressure range below 10 kPa, a detection limit as low as 0.98 Pa, a wide pressure response range of 300 kPa, and response and relaxation times of 13 ms, with exceptional mechanical stability, and flexibility of the pressure sensor is demonstrated to be suitable for detecting pulses and human movements, with significant potential in the fields of wearable devices and electronic skin.