Mycelium as a self-growing biobased material for the fabrication of single-layer masks

Disposable face masks are an essential piece of personal protective equipment for workers in medical facilities, laboratories, and the general public to prevent the spread of illnesses and/or contamination. Covid-19 resulted in an uptick in the usage and production of face masks, exacerbating issues related to the waste and recycling of these materials. Traditionally, face masks are derived from petrochemicals, such as melt-blown or spunbound polypropylene. As such, there is a need to find sustainable mask materials that can maintain or improve the performance of petrochemical masks. This paper explores an alternative mask material that utilizes fungal mycelium as self-growing filaments to enhance the efficiency of individual polypropylene mask layers. By engineering the growth pattern and time, breathability and filtration efficiency was optimized such that one layer of the mycelium-modified mask could replace all three layers of the traditional three-layer mask. Additionally, it was found that the mycelium-modified mask exhibits asymmetric hydrophobicity, with super-hydrophobicity at the composite-air interface and lower hydrophobicity at the composite-medium interface. This property can improve the performance of the modified mask by protecting the mask from external liquids without trapping water vapor from the user's breath. The findings from this study can provide a basis for further development of mycelium to create sustainable filtration materials with enhanced functionality.