A novel method to measure diffusion coefficients in porous metal–organic frameworks

Zybaylo, Olexandra; Shekhah, Osama; Wang, Hui; Tafipolsky, Maxim; Schmid, Rochus; Johannsmann, Diethelm; Wöll, Christof

doi:10.1039/b927601g

Cited by 151 publications

(172 citation statements)

References 29 publications

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“…Thermodynamics of the sorption process: It has been reported that thermodynamic properties such as activation energy and Gibbs free energy of the sorption processes can be evaluated from the QCM responses [45,46]. Knowledge of these properties can be valuable as a guide to determine how to increase the response, reversibility and reproducibility of future sensing materials.…”

Section: Neutron Measurements and Distribution Of Pnt In Filmmentioning

confidence: 99%

“…Knowledge of these properties can be valuable as a guide to determine how to increase the response, reversibility and reproducibility of future sensing materials. If we assume the diffusion of pNT into the dendrimer film follows a simple "site-hopping" model, the temperature dependence of the diffusivity can be written as [45] Page 10 of 24…”

Section: Neutron Measurements and Distribution Of Pnt In Filmmentioning

confidence: 99%

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Diffusion of nitroaromatic vapours into fluorescent dendrimer films for explosives detection

Ali¹,

Chen²,

Cavaye³

et al. 2015

Sensors and Actuators B: Chemical

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Abstract:Fluorescence-based sensing with organic semiconductors is a powerful method for the detection of a broad range of analytes including explosives, chemical weapons and drugs.Diffusion of an analyte into an organic semiconductor thin film, and its subsequent interaction with the chromophore are key factors that govern the sensing performance of a chemosensor.In this study the diffusion behaviour of an explosive analyte analogue into a sensing film of a conjugated dendrimer was investigated using a quartz crystal microbalance (QCM) and correlated with neutron reflectivity measurements. The mechanistic insights of paranitrotoluene (pNT) sorption in the films of different thicknesses of a first generation dendrimer with fluorenyl surface groups, carbazole dendrons and a spirobifluorene core were studied and interpreted in terms of the underlying kinetics and thermodynamics. Sorption measurements suggest that the process of diffusion of pNT vapour into the dendrimer films is Super Case II, which involves swelling of the film. Swelling of the film was confirmed by neutron reflectometry measurements, which also showed uniform distribution of the pNT molecules throughout the entire film thickness. The activation energy barrier and change in Gibbs free energy in the sorption process were calculated from the QCM responses. The sorption process was found to be thermodynamically (not kinetically) controlled and independent of film thickness. This work sheds insight into the structure-property relationships that govern the performance of organic semiconductor fluorescence-based chemosensors.

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Section: Neutron Measurements and Distribution Of Pnt In Filmmentioning

confidence: 99%

Section: Neutron Measurements and Distribution Of Pnt In Filmmentioning

confidence: 99%

Diffusion of nitroaromatic vapours into fluorescent dendrimer films for explosives detection

Ali¹,

Chen²,

Cavaye³

et al. 2015

Sensors and Actuators B: Chemical

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“…The QCM sensor was placed in a flow cell (Q-Sense E4). Infiltration with guest molecules was achieved via a flow of gas or a stream of liquid through the cell 25 . The SURMOF to be investigated was grown directly on the gold-coated QCM sensor after functionalization with a 16-mercaptohexadecanoic acid selfassembled monolayer (MHDA SAM).…”

Section: Uptake By Pristine Hkust-1 Surmofs Of Varying Thicknessesmentioning

confidence: 99%

“…Under adequate conditions, SURMOFs grow uniformly and film roughness as low as the size of a MOF unit cell can be achieved 23 . Apart from many potential applications, including chemical sensors and membranes, SURMOFs are well suited for a quantitative analysis of dynamic phenomena within MOFs [24][25][26] . In the present study we used HKUST-1, which is also known as Cu 3 ARTICLE commercially available 30 .…”

mentioning

confidence: 99%

The surface barrier phenomenon at the loading of metal-organic frameworks

2014

Self Cite

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Loading with guest molecules is a crucial step for most applications of porous materials. For metal-organic frameworks, which are one of the most intensely investigated classes of porous materials, the experimentally determined rate of mass transfer into the material may vary by several orders of magnitude for different samples of the same material. This phenomenon is commonly attributed to the presence of so-called surface barriers, which appear to be omnipresent but poorly understood. Here we quantitatively study this phenomenon with a quartz crystal microbalance, using well-defined, highly crystalline, epitaxially grown thin films of metal-organic frameworks as a model system. Our results clearly demonstrate that surface barriers are not an intrinsic feature of metal-organic frameworks, as pristine films do not exhibit these limitations. However, by destroying the structure at the outer surface, for instance by exposure to air or water vapour, surface barriers are created and the molecular uptake rate is reduced.

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“…[38][39][40] In QCM-D, the change in frequency of a quartz crystal resonator is monitored upon mass changes. The adsorbed mass, M f , and the frequency-shift, Δf n , are related by the Sauerbrey Equation (1)…”

Section: Preparation Of Nanoporous Films By Removal Of Templatementioning

confidence: 99%

Size‐Selective Binding of Sodium and Potassium Ions in Nanoporous Thin Films of Polymerized Liquid Crystals

Bögels

Lugger

Goor

2016

Adv Funct Materials

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The development of a nanoporous material from a columnar liquid crystalline complex between a polymerizable benzoic acid derivative and a 1,3,5‐tris(1H‐benzo[d]imidazol‐2‐yl)benzene template molecule is described. The morphology of the liquid crystalline complex is retained upon polymerization and quantitative removal of the template molecule affords a nanoporous material with the same lattice parameters. The nanoporous material selectively binds cations from aqueous solution, with selectivity for sodium and potassium ions over lithium and barium ions, as shown with FT‐IR. Binding is also quantified gravimetrically with a quartz crystal microbalance with dissipation monitoring, a technique that is used for this purpose for the first time here.

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A novel method to measure diffusion coefficients in porous metal–organic frameworks

Cited by 151 publications

References 29 publications

Diffusion of nitroaromatic vapours into fluorescent dendrimer films for explosives detection

Diffusion of nitroaromatic vapours into fluorescent dendrimer films for explosives detection

The surface barrier phenomenon at the loading of metal-organic frameworks

Size‐Selective Binding of Sodium and Potassium Ions in Nanoporous Thin Films of Polymerized Liquid Crystals

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