Wrinkled silica doped electrospun nano-fiber membranes with engineered roughness for advanced aerosol air filtration

Abstract

The engineering of the next generation of fibrous air membranes that exhibit high air filtration and quality factor performances are a critical challenge. Microfibrous air membranes typically exhibit high quality factors and low air filtration efficiency due to the large pore size structure. The development of nanofiber membranes with high surface area and textured surface is thus required to enhance the capturing properties. Herein, novel wrinkled, electrospun nanofiber nanocomposite membranes were successfully engineered by doping tetraethyl orthosilicate (TEOS) into poly (acrylonitrile) (PAN) for the sub-micron aerosol particle size filtration. The dopant silica in the PAN matrix increased the nonslip zones for particles across the surface of the fibers and generated larger stagnation zones for the particles capture. This strategy combined with the pore engineering design allowed by nanofibers, offered lower pressure drop across the membranes while maintaining separation efficiency. The Brunauer–Emmett–Teller (BET) specific surface of TEOS based membranes were found to be up two times higher than the bare PAN membranes. The wrinkled surface texturation and nano- porosity structure helped to enhance the air filtration performance compared to smooth bare PAN membranes and to commercial air filtration membranes. The quality factor of electrospun TEOS/PAN based membranes was also higher than the benchmarked commercial air membrane. This multifunctional membrane fabrication strategy opens new avenues for removing air pollutants including particulate matters, bacteria, viruses, and toxic gases, from air in a more cost-effective manner.