Flexible pressure sensors based on carbonized electrospun PAN fiber films containing ZIF-67 nanoparticles for human motion detection

In this work, flexible pressure sensors have been fabricated using carbonized electrospun polyacrylonitrile (PAN) fiber films embedded with ZIF-67 nanoparticles (denoted as C-ZIF-67@PAN). The incorporation of ZIF-67 nanoparticles into PAN fiber films facilitated interconnecting within the fiber network and also promoted fiber integrity, improving the electron conductivity of associated composite fiber films. Based on C-ZIF-67@PAN fiber films, the pressure sensors exhibited a broad operating range of 0-150 kPa, an exceptional detection sensitivity of 369.41 kPa-1, high structural stability of over 104 cycles, and a fast pressed/relaxed reaction (i.e., 44 ms/45 ms, respectively). Based on the prepared pressure sensors, various subtle signals for the human body, such as finger bending, finger pulses, and wrist pulses, can be detected. Also, an electronic skin with tactile perception was realized by fabricating a 5 x 5 sensing array on polyimide films. Furthermore, assisted by machine learning, the detection and recognition of handwriting based on a flexible pressure sensor affixed to a finger was accomplished. It is thus demonstrated that electrospun C-ZIF-67@PAN nanofiber films have great potential for use in applications such as artificial electronic skin, personal medical monitoring, medical diagnostics, and human-machine interactions.