Sterilization and Filter Performance of Nano‐ and Microfibrous Facemask Filters – Electrospinning and Restoration of Charges for Competitive Sustainable Alternatives

Facemask materials have been under constant development to optimize filtration performance, wear comfort, and general resilience to chemical and mechanical stress. While single-use polypropylene meltblown membranes are the established go-to material for high-performing mask filters, they are neither sustainable nor particularly resistant to sterilization methods. Herein an in-depth analysis is provided of the sterilization efficiency, filtration efficiency, and breathing resistance of selected aerosol filters commonly implemented in facemasks, with a particular focus on the benefits of nanofibrous filters. After establishing a general overview over face mask filters and machine washing parameters required for successful decontamination, respective changes in filter performance and structure are presented. Sustainably manufactured, highly efficient, but also more fragile electrospun membranes not only offer competitive performance as well as a more environment-friendly production and degradation process, but also support a subsequent sterilization and recharging approach via alcohol exposition and drying in an electric field. It is further elaborated on the prospective sustainability of each material to offer a clear outlook on electrospun membranes as the most promising filter membranes of the future.