Wearable room-temperature ethanol sensor based on Ti₃C₂T_x/Polypyrrole functionalized face mask for drunk driving monitoring

As one of the most encountered volatile organic compounds (VOCs), ethanol, especially with high blood con-centrations, could cause adverse effects such as nausea, vomiting, skin allergies, low blood pressure, low blood sugar, and Parkinson's disease, seriously threatening human health and safety driving. In this study, we demonstrate a wearable ethanol sensor through drop-coating Ti3C2Tx suspension followed by chemical poly-merization of pyrrole on a disposable face mask substrate. The as-fabricated PP/Ti3C2Tx/PPy composite sensor exhibited a rapid response/recovery speed (49s/18s), a good sensing response of 76.3 % toward 400 ppm ethanol, an admirable theoretical limit of detection of 2.21 ppm, reliable flexibility, high selectivity, and excellent reproducibility. The outstanding sensing characteristics of the composite sensor are ascribed to the abundant functional groups (e.g., amino groups in PPy, terminal groups in Ti3C2Tx) and the formation of the Schottky junction between Ti3C2Tx and PPy. Moreover, the composite sensor exhibits stable sensing performance around room temperatures (20-40 degrees C), and even at different bending states (0-150 degrees). In addition, we developed a portable and wearable Bluetooth sensor module for human alcohol breath detection, suggesting the PP/ Ti3C2Tx/PPy composite sensor can be used for human drunk driving monitoring and health assessment.