A strategy is developed to enhance the barrier protection of
polyethylene oxide (PEO)-
metal-organic framework (MOF) composite films against
chemical warfare agent simulants. To achieve enhanced protection, an impermeable high-aspect-ratio filler in the form of
Laponite RD (LRD)
clay platelets was incorporated into a composite PEO film containing MOF UiO-66-NH2. The inclusion of the platelets
aids in mitigating permeation of inert
hydrocarbons (
octane) and toxic chemicals (2-chloroethyl ethyl
sulfide, 2-
CEES) of dimensions/chemistry similar to prominent
vesicant threats while still maintaining high
water vapor transport rates (WVTR). By utilizing small-angle neutron scattering, small-angle X-ray scattering, and wide-angle X-ray scattering, the LRD platelet alignment of the films was determined, and the structure of the films was correlated with performance as a barrier material. Performance of the membranes against toxic chemical threats was assessed using permeation testing of
octane and 2-CEES, a common simulant for the
vesicant mustard gas, and breathability of the membranes was assessed using WVTR measurements. To assess their robustness, chemical exposure (in situ diffuse reflectance infrared Fourier transform spectroscopy) and mechanical (tensile strength) measurements were also performed. It was demonstrated that the barrier performance of the film upon inclusion of the LRD platelets exceeds that of other MOF-
polymer composites found in the literature and that this approach establishes a new path for improving permselective materials for chemical protection applications.