The iontronic sensor based on biodegradable polycaprolactone for interfacial capacitive pressure sensing

With the development of flexible wearable pressure sensors, capacitive pressure sensors using electric double-layer (EDL) effect have attracted much attention due to their advantages such as high sensitivity. In this study, an all-nanofiber ionic liquid EDL capacitive pressure sensor based on biodegradable polymer Polycaprolactone (PCL) is prepared by electrospinning technology. Based on the control of ionic liquid content in nanofibrous membranes, the performance of EDL capacitive pressure sensors has been investigated. The optimized device has a sensitivity of up to 26.4 kPa⁻¹ in the range of below 10 kPa and 6.2 kPa⁻¹ in the pressure range of 10 to 200 kPa. A detection limit as low as 8.53 Pa also gives it an advantage in detecting small pressures. Based on it, the prepared EDL capacitive pressure sensors have been successfully used to detect various physiological signals such as pulse, heartbeat, breathing, etc. In addition, the excellent mechanical properties and gas permeability also lay the foundation for its application in wearable electronics.