Fabrication of antibacterial nanofiber substrate using polyethylene terephthalate and copper nitrate to determine the efficiency of submicron particle filtration

Surgical masks are usually used to protect surgeons from the transmission of disease and germs, as well as preventing the transmission of infectious agents to the environment and others. The mask may not be a suitable environment for the growth and reproduction of microbes. Regarding this, the present study aimed to investigate the feasibility of making antibacterial mask substrate providing high efficiency and low pressure drop.
For the purpose of the study, nanofiber substrates containing variable amounts of polyethylene terephthalate and copper nitrate were produced using an electrospinning device. The efficiency and pressure drop of antibacterial nanofiber substrates were measured at a particle size range of 260 nm to 1.6 µ.  Measurement of the particle number density was accomplished by placing two condensation particle counters on both sides of the filter.
Examination of the scanning electron microscope images revealed that the optimal sample contained 25% polymer and 1.5% copper nitrate and had the best morphology at 16 kV. The samples were subjected to electrospinning at different times to examine their efficiency and pressure drop. As the electrospinning time increased from 15 to 60 min, the substrates became thicker, and consequently their efficiencies increased from 13% to 94%; furthermore, the pressure drop increased from 10 to 20 psi. Electrospinning of 60 min resulted in the highest quality factor.
As the findings indicated, with increasing of electrospinning time, the efficiency of the substrates will be increased and the particle penetration rate of the substrates will be reduced, which is due to increased thickness of substrates by increasing the electrospinning time.