What are nanofibers

In the scientific community nanomaterials are supposed to be not larger than 100 nm in at least one dimension.
In technology, particularly in sub-micron fibers, a different criterion is adopted. Namely, nanofibers are the fibers with a diameter of less than 500 nm. This is due to the fact that the tensile strength of the fibers sharply increases if their diameter is less than 500 nm. We also use this criterion.

The main feature of the nanofibers is their high specific surface area, i.e. the ratio of surface area to mass, which increases with decreasing diameter. This determines the scope of application of nanofibers - these are the areas where a large surface area is required: filter media, adsorbents, catalysts, catalyst supports, electrode materials, etc.