Structural design and development of multilayered polymeric nanofibrous membrane for multifaceted air filtration/purification applications

Developed a bilayered nanofibrous membrane, aimed to achieve a new class of air filtering media that can capture particulate matter, microbes and can also adsorb the harmful toxic gaseous components like formaldehyde (primary indoor pollutant). A layer of oriented nanofibers prepared via coaxial electrospinning with poly(m-phenylene isophthalamide) as core, polyacrylonitrile/polyethylenimine blended polymer as shell and another layer of randomly aligned nanofibers (polyacrylonitrile-silver nanoparticle nanofibers produced using single-nozzle electrospinning) were put together, to provide stable porous structure and induce multilevel filtration. The successful synthesis of this robust coaxial-based nanofibrous filter medium would not only make it a promising candidate for air filtration, but it will provide a new insight into designing and fabricating composite coaxial nanofiber-based membranes by incorporating various functional materials into shell for toxic gas adsorption related applications and the core can be of a mechanically robust material to address the easily collapsing cavity structure of nanofibers. The results revealed that the developed filter with superior mechanical property (11.88 MPa by virtue of poly(m-phenylene isophthalamide) fiber macromolecule that existed as rigid skeletal structure) can provide high removal efficiencies of 99.23% toward particulate matter, 99.6% toward bacterial aerosols, adsorb formaldehyde an indoor toxic gaseous pollutant and have potential antimicrobial effects against Escherichia coli and Bacillus subtilis while maintaining low pressure drop of 53.03 MPa, which to the best of our knowledge, has never been accomplished with a single filter medium before.