Highly tunable metal–organic framework (MOF) materials, including, for example, UiO-66-NH2, are known to be effective catalysts to degrade chemical warfare agents (CWAs) with half-lives near 1 min. Therefore, many researchers have been actively working on producing supported MOF materials to improve application effectiveness by using relatively slow solvothermal synthesis or repetitious stepwise layer-by-layer methods. Herein, we demonstrate a facile route to rapidly assemble presynthesized UiO-66-NH2 crystals onto nonwoven polypropylene (PP) fibrous mats at ambient temperature. Crystal assembly is chemically directed using β-cyclodextrin (β-CD) and cetyltrimethylammonium bromide (CTAB) as surfactant assembly agents, where the agents quickly (within 5 min) self-assemble on the crystal surface and promote physically robust chemical surface attachment while simultaneously impeding solution-phase crystal agglomeration. Furthermore, we find that when the PP is preconditioned using conformal metal oxide thin films, including Al2O3, TiO2, or ZnO formed via atomic layer deposition (ALD), the hydrophilic metal oxide surface further helps improve assembly uniformity and MOF mass loading, producing MOF crystal loading as high as 40 wt % and an overall BET surface area exceeding 200 m2/g(MOF+Fiber). Using these surface-assembled MOFs, we observe catalytic degradation of dimethyl 4-nitrophenyl phosphate (DMNP), a CWA simulant, with a half-life of less than 5 min.

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Atomic layer deposition (ALD) is a viable means to add corrosion protection to copper metal. Ultrathin films of AlO, TiO, ZnO, HfO, and ZrO were deposited on copper metal using ALD, and their corrosion protection properties were measured using electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry (LSV). Analysis of ∼50 nm thick films of each metal oxide demonstrated low electrochemical porosity and provided enhanced corrosion protection from aqueous NaCl solution. The surface pretreatment and roughness was found to affect the extent of the corrosion protection. Films of AlO or HfO provided the highest level of initial corrosion protection, but films of HfO exhibited the best coating quality after extended exposure. This is the first reported instance of using ultrathin films of HfO or ZrO produced with ALD for corrosion protection, and both are promising materials for corrosion protection.

Vapor-phase, metal-containing organic compounds can diffuse into polymers and modify the material composition and structure. In this work, using a sequential vapor infiltration process based on atomic layer deposition chemistry, we combine in situ Fourier transform infrared transmission and quartz crystal microbalance experiments with ab initio quantum chemical modeling analysis to evaluate and identify likely reaction mechanisms when poly(methyl methacrylate) (PMMA) thin films are exposed to trimethylaluminum (TMA) vapor. We find that TMA readily diffuses into the PMMA, where it physisorbs to ester carbonyl units (C]O) to form a metastable C]O/Al(CH 3 ) 3 adduct structure that desorbs at moderate temperatures (<100 C). The Lewis-acidic TMA withdraws charge from the C]O, shifting its stretching frequency from 1732 cm À1 in untreated PMMA to 1670 cm À1 after TMA exposure. At higher temperatures IR results show a new feature near 1568 cm À1 that is stable, even upon exposure to water vapor, indicating covalent bond formation. Based on known TMA-polymer reaction mechanisms and ab initio model results, we propose that at T > 100 C, TMA reacts with PMMA to form covalent resonant C]O/Al-O-C bonding units, and does not form -O-C-O-Al(CH 3 ) as previously hypothesized. This mechanistic insight will help elucidate other polymer/Lewis-acid vapor reactions and could enable new applications for sequential vapor infiltration processes.

The threat associated with chemical warfare agents (CWAs) motivates the development of new materials to providee nhanced protection with ar educed burden. Metalorganic frame-works (MOFs) have recently been shown as highly effective catalysts for detoxifying CWAs,but challenges still remain for integrating MOFs into functional filter media and/or protective garments.Herein, we report aseries of MOFnanofiber kebab structures for fast degradation of CWAs.W e found TiO 2 coatings deposited via atomic layer deposition (ALD) onto polyamide-6 nanofibers enable the formation of conformal Zr-based MOF thin films including UiO-66, UiO-66-NH 2 ,a nd UiO-67. Cross-sectional TEM images show that these MOF crystals nucleate and growdirectly on and around the nanofibers,with strong attachment to the substrates.These MOF-functionalized nanofibers exhibit excellent reactivity for detoxifying CWAs.T he half-lives of aC WA simulant compound and nerve agent soman (GD) are as short as 7.3 min and 2.3 min, respectively.T hese results therefore provide the earliest report of MOF-nanofiber textile composites capable of ultra-fast degradation of CWAs.