UC Davis

Face masks or facial coverings are used to protect wearers from inhalation of pollutants, viruses, and particulate matter. Many face masks are single-use and made of petroleum-based polymers. Used facemasks may contain infectious viral particles on the surfaces, leading to concerns of plastic waste accumulation and risk of cross contamination. The development of reusable, biobased, biodegradable and biocidal filtration materials for use in face masks will reduce the environmental impact of personal protective equipment and reduce risks of cross contamination. Polylactic acid (PLA), a biobased and biodegradable polymer, was explored as an alternative to replace the current olefin polymers as a facemask filtration material. PLA was combined with an edible photosensitizer (menadione, VK3) and successfully electrospun into fibrous membranes. The physical properties of the materials were explored to determine its capabilities as a filtration material. The photoactivity of the membranes were assessed to determine its use as an antibacterial material. The PLA-VK3 membrane resulted in adequate filtering efficiency, generation of Reactive Oxygen Species (ROS), and antibacterial properties. In this thesis, chapter 1 explores the benefits of face masks in preventing disease and the methodology behind filtration materials. It delves into the drawbacks and benefits of filtration materials used in face masks. It explores methods to decrease the environmental impact of face masks through the development of reusable, biocidal, biobased, and biodegradable filtration materials. In chapter 2, the properties of filtration materials made from polylactic acid (PLA), a biobased, biodegradable thermoplastic polymer. PLA was successfully electrospun into nanofibrous membranes that provide adequate pressure drop and filtration efficiency for use in face masks. It also explores different alterations to the PLA membrane that could improve its performance, such as PLASMA treatment and the addition of photosensitizers. In chapter 3, the use of a photosensitizer (VK3) as an antibacterial agent in PLA membranes was explored. VK3 was successfully electrospun with PLA to form an antibacterial filtration membrane. The VK3 within the membrane produces reactive oxygen species (ROS) under irradiation, which gives the membranes an antibacterial effect. The mechanical and physical properties of the membranes are also discussed to determine the connection between the material and its filtration properties. Chapter 4 provides a conclusion of the findings of PLA-VK3 electrospun membranes as new filtration material in face masks.