(315a) Rapid Production of MOF-Based Fabrics for Particulate Matter Pollution Filtration

Metal organic frameworks (MOFs) are highly functional porous coordination polymers composed of metal nodes periodically linked by organic acids. With designable pore geometry and chemical functionality, this class of materials has already proven to have considerable impact in heterogeneous catalysis, air filtration, separations, and electronic devices. One promising application for MOFs is their use to capture aerosolized particles, namely particulate matter below 2.5 μm (PM2.5) and aerosol transmitted diseases (ATD), which significantly influence mortality rate, public health outcomes, and the economy at a global scale. Filtration devices are often fabricated by growing MOF crystals on a textile-based or porous substrate where polluted air is then passed through the substrate to bring particulate matter within close proximity of MOF. Current methods of growing on fabric-based substrates require harsh organic solvents, long processing times, and small batch processes, which significantly limit the ability to scale production to impactful levels.

In this work, we develop a rapid thin film coating technique, termed sequential dip coating (SQD), where a substrate is sequentially dipped into a metal node solution and an organic linker solution to rapidly form a thin film of MOF at an interface developed on the substrate. In order to test air pollution filtration efficacy, we choose the highly stable and highly functionalize MOF, UiO-66-NH₂. By leveraging our rapid, interfacial technique, we demonstrate the MOF loading on commonly available woven cotton fabric can be tuned to grow thin films of UiO-66-NH₂ on the fiber surfaces with up to 20 wt% MOF on the time scale of seconds. This result is particularly interesting given the time scale of conventional coating techniques is on the order of minutes to hours. Further, we measure the pollution filtration performance of particulate matter between 1 and 4 microns (PM_1-4) to demonstrate up an 85% filtration efficiency for UiO-66-NH₂ loaded cotton. Finally, we will discuss the advantages of our rapid, thin film fabrication approach for device fabrication.