All‐Nanofiber Iontronic Sensor with Multiple Sensory Capabilities for Wearable Electronics

Abstract Wearable multi‐functional sensor with practical features is crucial for applications in many areas such as e‐skin, health monitoring, and human‐computer interaction. Herein, an all‐nanofiber flexible breathable iontronic sensor based on polyacrylonitrile (PAN) nanofiber membrane doped with ionic liquid (IL) is prepared by electrospinning technique. Compared to the traditional capacitor's electrode‐dielectric‐electrode sandwich structure, an undoped PAN nanofiber membrane is added between the electrode and the dielectric layer as the spacer. The iontronic sensor demonstrated an impressive linear response in pressure ranges of 0–50 and 50–300 kPa, with linearity values of R 1 2 = 0.992, R 2 2 = 0.998 by adjusting the thickness of the spacer. Additionally, the iontronic sensor demonstrates excellent temperature response attributed to the thermal sensitivity of the IL. It exhibits high sensitivities of 8.5, 31.8, and 71.1% °C −1 , along with low detection limits of 0.5°C, across temperature ranges of 20–40, 40–55, and 55–80 °C, respectively. To validate the sensor for practical applications, its uses are demonstrated in various scenarios, such as body joint flexion, heartbeat monitoring, encrypted messaging, and temperature‐sensitive gloves. This study enables the integration of pressure and temperature sensing functions to develop diverse and integrated designs for wearable electronic devices.