Free volume, gas permeation, and proton conductivity in MIL-101-SO3H/Nafion composite membranes

Variations of ortho-positronium (o-Ps) lifetime and gas permeability of the Aquivion® E8705 membrane were studied as functions of temperature under vacuum and relative humidity at room temperature. When the temperature was varied between 0 and 100 °C in vacuum, the hole volume of Aquivion® E8705, deduced from the ortho-positronium lifetime, gradually increased. However, when the relative humidity was changed at room temperature, the hole volume was essentially unchanged. Good linear correlations between the logarithm of permeabilities of O2 and H2 and reciprocal hole volume at different temperatures indicates the importance role of free volume in gas permeation in dry Aquivion® E8705. However, for hydrated Aquivion® E8705 the permeability less depends on hole volume.

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Ion Beam Irradiation—An Efficient Method to Modify The Subnanometer Scale Microstructure of Polymers In A Controlled Way

MRS Proceedings ◽

10.1557/proc-540-255 ◽

1998 ◽

Vol 540 ◽

Cited By ~ 6

Author(s):

Xinglong Xu ◽

M. R. Coleman ◽

U. Myler ◽

P. J. Simpson

Keyword(s):

Ion Irradiation ◽

Gas Permeability ◽

Ion Beam ◽

Composite Membranes ◽

Positron Annihilation Spectroscopy ◽

Gas Permeation ◽

Beam Irradiation ◽

Ion Beam Irradiation ◽

Application Potential ◽

Promising Application

AbstractThe microstructural evolution of polymers induced by ion beam irradiation was investigated using gas permeation measurements with different molecule size gases and positron annihilation spectroscopy (PAS) using variable-energy positron. Simultaneous large increases in gas permeability and permselectivity of polymer-ceramic composite membranes modified by 180 keV H+ ion irradiation indicated that ion irradiation of polymers can modify the microstructure of polymer at sub-nanometer level in a controlled way. PAS results were consistent with the gas permeation results. The results of this work demonstrated ion beam irradiation has a promising application potential in the separation industry.

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Correlation of gas permeation and free volume in new and used high free volume thin film composite membranes

Journal of Polymer Science Part B Polymer Physics ◽

10.1002/polb.23616 ◽

2014 ◽

Vol 53 (3) ◽

pp. 213-217 ◽

Cited By ~ 23

Author(s):

Toenjes Koschine ◽

Klaus Rätzke ◽

Franz Faupel ◽

Muntazim Munir Khan ◽

Thomas Emmler ◽

...

Keyword(s):

Thin Film ◽

Free Volume ◽

Composite Membranes ◽

Gas Permeation ◽

Film Composite ◽

Thin Film Composite

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Molecular Dynamics Simulation Study of Solid Vibration Permeation in Microporous Amorphous Silica Network Voids

Membranes ◽

10.3390/membranes9100132 ◽

2019 ◽

Vol 9 (10) ◽

pp. 132

Author(s):

Yoshioka ◽

Nakata ◽

Tung ◽

Kanezashi ◽

Tsuru

Keyword(s):

Molecular Dynamics ◽

Amorphous Silica ◽

Gas Permeability ◽

Polymer Network ◽

Gas Permeation ◽

Dynamics Simulation ◽

Silica Membrane ◽

Silica Membranes ◽

Gas Diffusivity ◽

Gas Molecules

Microporous silica membranes have silica polymer network voids smaller than 3 Å where only small gas molecules such as helium (2.6 Å) and hydrogen (2.89 Å) can be transported. These silica membranes are highly expected to be available for H2 separation. In order to examine gas permeation mechanisms in the silica polymer network voids, factors such as membrane porous structures, gas diffusivity, and gas permeability were studied via membrane permeation molecular dynamics simulation. The thermal motions of silica membrane constituent atoms were examined according to classic harmonic oscillation potential using a suitable amorphous silica structure and non-equilibrium molecular dynamics (NEMD) simulations of gas permeation. The dynamic model successfully simulated the gas permeation characteristics in an amorphous silica membrane with a suitable Hooke’s potential parameter. The introduction of the oscillative thermal motion of the membrane atoms enhanced gas diffusivity. Helium and hydrogen diffusivity and permeability were analyzed using gas translation (GT) and solid vibration (SV) models. The diffusion distance of gas molecules between adsorption sites was around 5.5–7 Å. The solid-type vibration frequencies of gas molecules in the site were on the order of 1013 and were reasonably smaller for heavier helium than for hydrogen. Both the GT and SV models could explain the temperature dependency of helium and hydrogen gas diffusivities, but the SV model provided a more realistic geometrical representation of the silica membrane. The SV model also successfully explained gas permeability in an actual silica membrane as well as the virtual amorphous silica membrane.

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Preparation and Characterization of AgA Zeolite/Polysulfone Membranes

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.549.401 ◽

2012 ◽

Vol 549 ◽

pp. 401-405

Author(s):

Tian Ming Zhang ◽

Zhen Huang ◽

Xiao Hong Zhang ◽

Li Ying Guo

Keyword(s):

Ion Exchange ◽

Gas Permeability ◽

Composite Membranes ◽

Gas Permeation ◽

Silver Ion ◽

Interfacial Interactions ◽

Polysulfone Membrane ◽

Characterization Methods ◽

Permeation Test

In present study, a few polysulfone composite membranes with the introduction of silver ion-exchange treated zeolite were prepared and evaluated by several characterization methods. Regularly-ordered zeolite particles were generally finely dispersed in the continuous PSF phase with appreciated organic-inorganic interfacial interactions as reflected by SEM and FTIR results. Gas permeation test shows that after incorporating zeolite the polysulfone membrane exhibits significantly decreased gas permeability for H2, N2, and CO2 whereas they show increased permselectivity for CO2/N2, H2/CO2 and H2/N2 gas pairs as compared to neat polysulfone membrane.

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Polyphenylsulfone (PPSU)-Based Copolymeric Membranes: Effects of Chemical Structure and Content on Gas Permeation and Separation

Polymers ◽

10.3390/polym13162745 ◽

2021 ◽

Vol 13 (16) ◽

pp. 2745

Author(s):

Fan Feng ◽

Can-Zeng Liang ◽

Ji Wu ◽

Martin Weber ◽

Christian Maletzko ◽

...

Keyword(s):

Free Volume ◽

Gas Separation ◽

Chemical Structure ◽

Gas Permeability ◽

Life Time ◽

Gas Permeation ◽

Polymer Chains ◽

Polymer Materials ◽

Fractional Free Volume ◽

Trade Off

Although various polymer membrane materials have been applied to gas separation, there is a trade-off relationship between permeability and selectivity, limiting their wider applications. In this paper, the relationship between the gas permeation behavior of polyphenylsulfone(PPSU)-based materials and their chemical structure for gas separation has been systematically investigated. A PPSU homopolymer and three kinds of 3,3′,5,5′-tetramethyl-4,4′-biphenol (TMBP)-based polyphenylsulfone (TMPPSf) copolymers were synthesized by controlling the TMBP content. As the TMPPSf content increases, the inter-molecular chain distance (or d-spacing value) increases. Data from positron annihilation life-time spectroscopy (PALS) indicate the copolymer with a higher TMPPSf content has a larger fractional free volume (FFV). The logarithm of their O2, N2, CO2, and CH4 permeability was found to increase linearly with an increase in TMPPSf content but decrease linearly with increasing 1/FFV. The enhanced permeability results from the increases in both sorption coefficient and gas diffusivity of copolymers. Interestingly, the gas permeability increases while the selectivity stays stable due to the presence of methyl groups in TMPPSf, which not only increases the free volume but also rigidifies the polymer chains. This study may provide a new strategy to break the trade-off law and increase the permeability of polymer materials largely.

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Thickness Effect on CO2/N2 Separation in Double Layer Pebax-1657®/PDMS Membranes

Membranes ◽

10.3390/membranes8040121 ◽

2018 ◽

Vol 8 (4) ◽

pp. 121 ◽

Cited By ~ 12

Author(s):

Roman Selyanchyn ◽

Miho Ariyoshi ◽

Shigenori Fujikawa

Keyword(s):

Double Layer ◽

Gas Permeability ◽

Composite Membranes ◽

Gas Permeation ◽

Thickness Effect ◽

Organic Polymer ◽

Porous Support ◽

Model Predictions ◽

Layer Membrane ◽

In Series

The effect of thickness in multilayer thin-film composite membranes on gas permeation has received little attention to date, and the gas permeances of the organic polymer membranes are believed to increase by membrane thinning. Moreover, the performance of defect-free layers with known gas permeability can be effectively described using the classical resistance in series models to predict both permeance and selectivity of the composite membrane. In this work, we have investigated the Pebax®-MH1657/PDMS double layer membrane as a selective/gutter layer combination that has the potential to achieve sufficient CO2/N2 selectivity and permeance for efficient CO2 and N2 separation. CO2 and N2 transport through membranes with different thicknesses of two layers has been investigated both experimentally and with the utilization of resistance in series models. Model prediction for permeance/selectivity corresponded perfectly with experimental data for the thicker membranes. Surprisingly, a significant decrease from model predictions was observed when the thickness of the polydimethylsiloxane (PDMS) (gutter layer) became relatively small (below 2 µm thickness). Material properties changed at low thicknesses—surface treatments and influence of porous support are discussed as possible reasons for observed deviations.

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Structure–Property Relationship on the Example of Gas Separation Characteristics of Poly(Arylene Ether Ketone)s and Poly(Diphenylene Phtalide)

Membranes ◽

10.3390/membranes11090677 ◽

2021 ◽

Vol 11 (9) ◽

pp. 677

Author(s):

Alexandre Alentiev ◽

Sergey Chirkov ◽

Roman Nikiforov ◽

Mikhail Buzin ◽

Oleg Miloserdov ◽

...

Keyword(s):

Experimental Data ◽

Glass Transition ◽

Transition Temperature ◽

Free Volume ◽

Gas Permeability ◽

Gas Permeation ◽

Transport Parameters ◽

Arylene Ether ◽

Ether Ketone ◽

And Diffusion

Three poly(arylene ether ketone)s (PAEKs) with propylidene (C1, C2) and phtalide (C3) fragments, and one phtalide-containing polyarylene (C4), were synthesized. Their chemical structures were confirmed via 1H NMR, 13C NMR and 19F NMR spectroscopy. The polymers have shown a high glass transition temperature (>155 °C), excellent film-forming properties, and a high free volume for this polymer type. The influence of various functional groups in the structure of PAEKs on gas transport parameters was evaluated. Expectedly, due to the higher free volume, the introduction of the hexafluoropropylidene group to PAEK resulted in a higher increase of gas permeability in comparison with the propylidene group. The substitution of the fluorine-containing group on a rigid phtalide moiety (C3) significantly increases the glass transition temperature of the polymer, while the gas permeation slightly decreases. Finally, the removal of two ether groups from the PAEK structure (C4) leads to a rigid polymer chain that is characterized by the highest free volume, gas permeability, and diffusion coefficients among the PAEKs under investigation. Also, theoretically predicted transport parameters were investigated, to further study the structure–properties relationship for the PAEKs. Methods of modified atomic (MAC) and bond (BC) contributions were applied for this purpose (estimation of gas permeation and diffusion). Gas solubility coefficients for PAEKs were forecasted by the “Short polymer chain surface based prediction” (SPCSBP) method. Both the MAC and BC techniques showed reasonable predicted parameters for three polymers, while a significant underestimation of gas transport parameters was observed for C4. The results for all three prediction methods were compared with the experimental data obtained in this work. The predicted parameters were in good agreement with the experimental data for phtalide-containing polymers (C3 and C4), while for propylidene-containing poly(arylene ether ketone)s they were overestimated, due to a possible influence of the propylidene fragment on the indices of the oligomeric chains. MAC and BC methods demonstrated a better prediction power than the SPCSBP method.

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Sulfonated poly(arylene ether sulfone) functionalized polysilsesquioxane hybrid membranes with enhanced proton conductivity

e-Polymers ◽

10.1515/epoly-2020-0048 ◽

2020 ◽

Vol 20 (1) ◽

pp. 430-442 ◽

Cited By ~ 2

Author(s):

Rajdeep Mukherjee ◽

Arun Kumar Mandal ◽

Susanta Banerjee

Keyword(s):

Proton Conductivity ◽

Sol Gel ◽

Composite Membranes ◽

Casting Technique ◽

Force Microscopy ◽

Arylene Ether ◽

Transmission Electron ◽

Uniform Dispersion ◽

Solution Casting Technique ◽

Sulfonated Poly

AbstractSulfopropylated polysilsesquioxane and –COOH containing fluorinated sulfonated poly(arylene ether sulfone) composite membranes (SPAES-SS-X) have been prepared via an in situ sol–gel reaction through the solution casting technique. The composite membranes showed excellent thermal and chemical stability, compared to the pristine SPAES membrane. The uniform dispersion of the sulfonated SiOPS nanoparticles on the polymer matrix was observed from the scanning electron microscope images. Atomic force microscopy and transmission electron microscopy images indicated significantly better phase-separated morphology and connectivity of the ionic domains of the composite membranes than the pristine SPAES membrane. The composite membranes showed considerable improvement in proton conductivity and oxidative stability than the pristine copolymer membrane under similar test conditions.

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Multi-cycle reversible control of gas permeability in thin film composite membranes via efficient UV-induced reactions

Chemical Communications ◽

10.1039/d0cc08238d ◽

2021 ◽

Vol 57 (27) ◽

pp. 3391-3394

Author(s):

Abdalrahman U. Alrayyes ◽

Ze-Xian Low ◽

Huanting Wang ◽

Kei Saito

Keyword(s):

Thin Film ◽

Polymer Coating ◽

Gas Permeability ◽

Composite Membranes ◽

Polymer Structure ◽

Film Composite ◽

Thin Film Composite ◽

Thin Polymer

This communication reports the use of light to reversibly constrict or ease the flow of oxygen through a very thin polymer coating. This is achievable by reversibly changing the polymer structure from a dense and rigid film to a loose and soft film.

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