Multifunctional sensors for respiration monitoring and antibacterial activity based on piezoelectric PVDF/BZT-0.5BCT nanoparticle composite nanofibers

In clinical practice, combining sensitive and efficient sensors that have antibacterial properties with masks is a convenient way to monitor vital signs. Therefore, developing flexible pressure sensors with high sensitivity and antibacterial properties is the key for such smart devices. In our work, poly (vinylidene fluoride) (PVDF) nanofibers (NFs) with a high piezoelectric phase were fabricated by electrospinning with an optimized spinning voltage and collecting roller speed. Ba(Ti_0.8Zr_0.2)O₃-0.5(Ba_0.7Ca_0.3)TiO₃ (BZT-0.5BCT) nanoparticles (NPs) synthesized by the hydrothermal method were introduced into PVDF NFs to improve their piezoelectric response to external strain. With 20 wt% 0.5BZT-BCT NPs, the PVDF/BZT-BCT fiber composite sensor showed an output voltage up to 6.37 V with superior sensitivity (0.24 V Kpa⁻¹), a short response time (∼50 ms), good durability over a wide time range and a low detection limit (2.50 mg). The sensor was built in a mask that demonstrated high sensitivity in monitoring the respiratory rate as well as antimicrobial resistance to Echerichia coli (E. coli) and Staphylococcus aureus (S. aureus). Furthermore, this composite fiber sensor can also be applied for the detection of body movement. The multifunctional 0.5BZT-BCT/PVDF fiber composite sensor may find clinical applications.