Spider-Net Structures in Electrospun Poly(vinyl alcohol)/Chitosan Nanofibers for Airborne Nanoparticle Filtration

High Resolution Image Download MS PowerPoint Slide “Spider-net” structures, nanometric web-like formations between electrospun fibers, have demonstrated significant potential for air filtration by enhancing material porosity and particle capture efficiency. However, their application has been primarily explored in synthetic polymers, raising concerns regarding environmental sustainability. This study investigates the formation and optimization of spider-nets in poly(vinyl alcohol) (PVA) and chitosan (CS) blends and their impact on fine and ultrafine particle filtration. A multilevel factorial design was employed to model the influence of polymer composition on fiber morphology, investigating spider-net coverage while preventing fiber fusion and film formation. Electrospinning was performed at an optimized electric field of 23.4 kV and a flow rate of 1.17 mL/h for 28 min. Spider-net coverage was mainly governed by PVA concentration, with CS acting to reduce its extent. To further modify spider-net morphology and enhance filtration performance, additives such as citric acid (Cit), cetyltrimethylammonium bromide (CTAB), and Lippia sidoides essential oil (EO) in pure and nanostructured lipid carrier (NLC) forms were incorporated. The presence of additives significantly altered the fiber network and its coverage, with the EO sample achieving the highest collection efficiency (99.6%), followed by Cit (99.3%). Both samples complied with the strictest international standards for face mask filtration (N95/N98), maintaining efficiencies above 98.0% with pressure drops of less than 40 Pa·cm –2 . This study advances the understanding of spider-net formation mechanisms and their impact on air filtration in biodegradable polymers. By controlling electronetting, we enhanced filtering performance, offering a sustainable alternative and opening windows for broader applications in environmental and biomedical fields.