A Highly Sensitive, Breathable, and Biocompatible Wearable Sensor Based on Nanofiber Membrane for Pressure and Humidity Monitoring

Abstract With the advent of information technology, the progress of wound healing diagnosis and human health monitoring bring forward the need for sensitive humidity sensing. Simultaneously, developing a highly sensitive humidity sensor with multifunctional characteristics, especially pressure sensing, biosafety, and comfort, remains challenging so far. Herein, a wearable humidity‐pressure sensor based on an all‐nanofiber membrane with excellent sensitivity, breathability, and biosafety is fabricated by the combination of electrospinning and screen‐printing. The citric acid (CA) and sodium polystyrene sulfonate (PSS) are used as moisture‐sensitive materials to make thermoplastic polyurethane (TPU) nanofiber membranes sensitive to water molecules. The synergistic effect of the uneven surface and microstructure of the electrospun TPU nanofiber membrane confers the sensor with high sensitivity to both humidity and pressure stimuli. The CA/TPU humidity‐pressure sensor exhibits remarkable breathability and high sensitivity (2.15%/RH in the range of 50–90%RH, 10.53 kPa −1 in the range of 0–2.25 kPa), as well as fast humidity response (3.8 s) with little hysteresis and rapid pressure response (88 ms). The high biosafety makes it applicable to skin and wounds. Furthermore, the sensor can detect various human activities in real‐time and offer a new sensing platform for respiratory monitoring and smart wound dressings.