Efficiency of media is related to the size of the fibers, as discussed above. Generally, the smaller the fiber, the higher the efficiency. Nanofiber fiber media can be made by many means. The most common technique employed in air filtration is electrospinning. In this process, the polymer is dissolved and fed through capillary tubes under a high potential field. The resulting fibers are nanometer in size and extremely uniform. A thin layer of nanofibers can markedly increase the efficiency of the open substrate.
The drawback of the technology is that the nanofibers layer is very thin, and therefore, relatively weak. It can degrade quickly in harsh and chemical environments. To achieve high filtration efficiency, a large number of nanofibers are required, but the flat morphology of the nanofiber fiber media can increase the pressure drop substantially.
