Topography and electrostatic interactions of electret fibres in N95 facemasks

Facemasks have been a critical line of defense in the Covid-19 pandemic and used for decades to reduce inhalation sub-micron aerosols, including bacteria, viruses nano-materials. These facemasks leverage electrostatic charge properties non-woven electret fibre mats remove aerosols. However, topographical these not well characterized at nano-scale. In this study, we use atomic force microscopy (AFM) examine surface topography fibres within commercial respirator mat, map interactions emanating from fibres, synchrotron X-ray scattering probe polymer morphology. We find that exhibit significant heterogeneity topography, polypropylene phase composition. The topographies ranged nano-smooth surfaces ordered spherulitic structures. varied across length circumference, are only weakly correlated with features. Finally, AFM characterize after filtering NaCl aerosol deposited particles heterogeneous size distributed over surfaces.