Durability and physical characterization of anti-fogging solution for 3D-printed clear masks and face shields

Abstract

The COVID-19 pandemic brought forth the crucial roles of personal protective equipment (PPE) such as face masks and shields. Additive manufacturing with 3D printing enabled customization and generation of transparent PPEs. However, these devices were prone to condensation from normal breathing. This study was motivated to seek a safe, non-toxic, and durable anti-fogging solution. We used additive 3D printing to generate the testing apparatus for contact angle, sliding angle, and surface contact testing. We examined several formulations of carnauba wax to beeswax in different solvents and spray-coated them on PETG transparent sheets to test contact and sliding angle, and transmittance. Further, the integrity of this surface following several disinfection methods such as detergent, isopropyl alcohol, or water alone with gauze, paper towels, and microfiber, along with disinfectant wipes, was assessed. The results indicate a 1:2 ratio of carnauba to beeswax in Acetone optimally generated a highly hydrophobic surface (contact angle 150.3 ± 2.1° and sliding angle 13.7 ± 2.1°) with maximal transmittance. The use of detergent for disinfection resulted in the complete removal of the anti-fogging coating, while isopropyl alcohol and gauze optimally maintained the integrity of the coated surface. Finally, the contact surface testing apparatus generated a light touch (5,000 N/m2) that demonstrated good integrity of the antifogging surface. This study demonstrates that a simple natural wax hydrophobic formulation can serve as a safe, non-toxic, and sustainable anti-fogging coating for clear PPEs compared to several commercial solutions.