Fabrication and Characterization of Eucalyptus-Incorporated Polyvinyl Alcohol Core–Shell Electrospun Nanofibrous Filter Media for Breath Mask Application

Unpleasant breathing can occur due to bad odors from wearing a medical mask. Electrospinning has been used to incorporate Eucalyptus extract into polyvinyl alcohol (PVA) to overcome the problem of medical masks and as an alternative, as part of an antiflu breathing face mask. This research aims to extend the shelf life of the pleasant odor by encapsulating Eucalyptus essential oil (EO) in nanofibers by coaxial electrospinning. Initially, nanofibers were produced using a blend structure of Eucalyptus aqueous extract (EA) and PVA, along with a core–shell structure of EO and PVA by electrospinning. The morphology of the nanofibers was investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), showing average diameters of 270 ± 47 nm for the blend nanofibers and 343 ± 126 nm for the core–shell nanofibers. TEM confirmed a core–shell structure presumably caused by the nonmiscibility of EO and PVA, as well as the high viscosity of the PVA solution. The loading capacity (LC) and encapsulation efficiency (EE) were calculated for the core–shell nanofibers to be 16.43 ± 3.29 and 55.20 ± 2.31, respectively. The presence of EO in the nanofibers was shown through FT-IR spectroscopy. At the same time, variations in peak intensity allowed tracing the displacement of EO and the aging of the nanofibers. A released study showed that after 7 hours of release in a conditioning room with 30°C and 70% humidity, the percentages of remaining Eucalyptol in the nanofibers were 68.36% and 83.63% for the blend and the core–shell structure, respectively. The size of the pores in these nanofibers on a layer ranged from 50 nm to 200 nm.