Electrospun nanofibers and spray-coating with silver nanoparticles for antiviral and antibacterial textiles

Silver nanoparticles (AgNPs) exhibit much higher antibacterial efficacy than in bulk. This work reports the results on antiviral/antibacterial properties of AgNPs in polyvinyl alcohol (PVA) matrix against SARS-CoV-2, Escherichia coli and Staphylococcus aureus. The protective coating was applied on textiles as a nanofiber layer by electrospinning and as a film by spray-coating. The materials used are AgNPs at 0.1% w/w in water solutions of PVA (molecular weight 130 kDa, hydrolysis degree > 99%) at the volume ratio 1:1. PVA concentrations were 1% w/v for spraying and 15% w/v for electrospinning. The substrates used were 16-μm polypropylene spun-bonded non-woven (23 g/m2), polyamide 66 fabric (59 g/m2), and polyethylene terephthalate fabric (130 g/m2). AgNPs/PVA dispersions were electrospun at +30 kV at the tip and -5 kV at the collector (50×50 cm). The PP spun-bonded non-woven was cut into squares of the same size as the collector and stuck on it. The addition of AgNPs destabilized the electrospinning, producing multiple jets instead of a single jet from the metal tip as usual. The AgNPs/PVA nanofibers were treated in an oven at 155°C for 3 minutes to fix the nanofibrous porous structure making them water-stable. Spray-coating was performed using 5 mL of AgNPs/PVA dispersion on 20×20 cm specimens, then dried in an oven at 80°C for 2 minutes. Washing tests were performed according to ISO 105-C06 at 40°C for 30 minutes with ECE detergent. Abrasion tests were performed according to ISO 12947-2 with 12 kPa loading. The virucide activity of AgNPs/PVA spray-coated substrate was reduced by 33% compared to the untreated substrate. While AgNPs/PVA spray-coated substrates showed 100% bacterial reduction against both bacteria. The spray-coated fabrics were stable to washing and abrasion. AgNPs/PVA electrospun nanofibers showed excellent bacteria reductions (> 99%). Funding: SANOSIL Project, SAC AD002 173 093