Highly Breathable Chemically Protective MOF‐Fiber Catalysts

Abstract

Fibrous composite materials provide distinct advantages in large surface area and enhanced molecular transport through the media, lending themselves to diverse applications. Despite substantial development in synthetic methods, it is still lacking in insights into structure-property relationships that can correlate features of the functional materials to absorptive, transport, and catalytic performance of the composites. Herein, for the first time, a systematic structure-property-function analysis is provided for Zr-based metalorganic frameworks (MOFs) coated onto polypropylene nonwoven textiles. MOF fraction on the fabric and defect density in MOF microstructures are controlled by an in situ seeded growth, where fiber surfaces are pretreated with metal-oxide by atomic layer deposition. The best performing MOF-fiber composite shows a rapid catalytic hydrolysis rate for a chemical warfare agent simulant, p-nitrophenyl phosphate with t 1/2 < 5 min, and a significant permeation restriction of a real agent GD-vapor through the composite. Of added advantage is the observed moisture vapor transport rate of 15 000 g m −2 day −1 for the composite, which is notably superior to that of other commercially available chemical-protective fabrics. The chemical-protective composites realized in this work overcome the breathability/detoxification trade-off and show promise for the materials to be deployed in a realistic field.

Porous textile composites (PTCs) for the removal and the decomposition of chemical warfare agents (CWAs) – A review

“…Without co-catalyst, the use of MOFs and textiles against nerve agents have been focused on the GD detoxification [160,210,247,298,303,304]. Using polyvinylidene fluoride PVDF/ UiO-66-NH 2 composite fabrics with a loading of 33 wt% of MOF, a half-life of 131 min was measured [303].…”

“…Another long degradation time was measured using a polyamide PA/UiO-66-NH 2 sample, with 65 % GD degradation after 24 h, despite reasonable MOF content ($10 wt%) and specific surface area (108 m 2 / g) [247]. Recently, a PP/TiO 2 /UiO-66-NH 2 was used to study GD diffusion and degradation, but also the breathability capacity of the composite [304]. It showed a good detoxification capacity with a half-life of 177 min while keeping a high moisture vapor transport rate (MVTR, 15600 g.m À2 .day À1 ) and impeding GD diffusion through the material.…”

“…To understand the effect of NEM, Zr-based MOFs (UiO-66, UiO-66-NH 2 and NU-1000) were tested for DMNP detoxification in pure water or in NEM solution (0.45 M) [244,257,304,305]. While the determined degradation was below 50 % after 24 h in pure water, UiO-66-NH 2 and NU-1000 presented half-life under 10 min in presence of NEM [305].…”

“…High degradation efficiencies towards DMNP (i.e. half-lives under 10 min) with UiO-66-NH 2 composites were obtained either using the photothermal effect [244,251,306], some specific synthesis deposition [224,246,247] or by adding an intermediate ALD layer between the fiber and the MOF [253,257,258,304]. The photothermal method converts photon into heat thanks to photothermal agents such as polydopamine (PDA) or graphene.…”

Dual-Function Detoxifying Nanofabrics against Nerve Agent and Blistering Agent Simulants

“…From an engineering point of view, the combination of detoxification materials with fabrics can not only play a comprehensive role in the protection and degradation of CWAs but also facilitate the recovery and reuse of catalysts. Therefore, methods to detoxify CWAs by loading catalytic materials on fibrous membranes or fabrics have attracted increasing attention. ,− By direct electrospinning MOF dispersion, − or integration of electrospray and electrospinning, ,, nanofibrous materials with high MOF loadings were obtained quite conveniently; however, the detoxification performance could be affected by the blocking of MOF catalytic sites and/or weak binding force between MOF particles and the fibrous substrates. To avoid this, another strategy aims to immobilize MOFs on the fiber surface by in situ growth or self-assembly, but common polymeric substrates do not provide sufficient nucleation sites or affinity, and therefore, the modification of the fiber surface has become the focus of research. − For example, Parsons’ group successfully achieved the assembly or in situ growth of dense MOF coatings on fibrous polymer substrates assisted by atomic layer deposition of metal oxides (Al 2 O 3 , ZnO, TiO 2 , etc.…”