Ultra-High Sensitive Ionotronic Pressure Sensor Based on ZIF-67 Decorated PVDF-HFP@IL Nanofibers for Lip Motion Detection

In this work, we developed an ultra-high sensitive flexible ionotronic pressure sensor (IPS) with wide working range by newly integrating a zeolitic imidazolate framework (ZIF)-67 decorated ionic nanofibrous membrane (INM) for lip motion detection. The INM layer sandwiched between graphene based ionic polymer electrodes control over the ion mobility through reverse pumping mechanism and lowers the initial capacitance, significantly improving the overall performance of the proposed IPS. The pressure sensor exhibited an excellent sensitivity over broad linear ranges: <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$4,628\ \text{kPa}^{-1}$</tex> (0-100 kPa), <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$17,982\ \text{kPa}^{-1}$</tex> (100-500 kPa), and 4,162 kPa (500-1,000 kPa) with fast response time (270 ms). The developed sensor showed stable response over 15k cycles demonstrating its reliability and robustness. Finally, the sensor was mounted and demonstrated on the inner wall of a commercially available face mask to monitor various stimuli generated during the articulation of vowels, words, and sentences.