Effect of Different Symmetries of Electrospun Poly(lactic acid) Nanofibers on Facemask Filtration

The Covid-19 pandemic has prompted the use of disposable facemasks, which has raised serious environmental concerns. Thus, we developed ultrafine electrospun masks comprising eco-friendly and biodegradable polymer polylactic acid, spun with different degrees of fiber alignments, ranging from random to less, medium, and highly aligned nanofibers. The filtration performance was assessed by penetrating sodium chloride (NaCl) aerosol particles (mean diameter 0.25 μm). The LA-NF samples exhibited a homogeneous network of fibers and thus even pore size distribution. The homogeneity of flow is generally accompanied by a decreased value of pressure drop. Such flow through the gaps (pores) created between the fibers follows Bernoulli’s principle, which revealed an extremely decreased value of pressure drop of 96 Pa and yielded a high filtration efficiency of 99.998% and a Qf of 0.17 Pa–1. The presence of static charges on membranes varies according to the geometry of the surface, which provides a strong electrostatic force between fine particulates and the charged surface. Moreover, a comparative study of static chargeability of the less aligned sample and conventional polypropylene filter was conducted, which revealed mean potential values of 67.1 and 60.8 V, respectively. The outcome implies the superior characteristics of the former, which can be attributed to the surface geometry of the structured membrane.