Phase separation in perfluorosulfonate ionomer membranes

Roche, E. J.; Pinéri, M.; Duplessix, R.

doi:10.1002/pol.1982.180200109

Cited by 83 publications

(82 citation statements)

References 8 publications

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“…[40,41] At the same time, Roche et al studied Nafion membranes by SANS and obtained similar results. [42] They confirmed that the broad maximum observed at low angles was related to the crystalline nature of the polymer matrix since it vanishes for a quenched sample (thermal treatment at 330 C and quenching in liquid nitrogen). A neutron contrast variation was used to show that most of the water molecules were located inside the ionic aggregates.…”

Section: The Former Studiessupporting

confidence: 71%

Neutron and X‐ray Scattering: Suitable Tools for Studying Ionomer Membranes

2005

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Neutrons and x‐rays were extensively used to study the microstructure of the polymeric membranes for fuel cells. The small‐angle x‐ray and neutron scattering (SAXS and SANS resp.) data for Nafion® and alternative membranes present specific features. The different analyses and proposed models to interpret these data are reviewed. A special emphasis is devoted to the recent elongated polymer particle model which appears as the most efficient model for Nafion® to interpret not only the numerous scattering data but also the transport swelling and mechanical properties. Neutrons can also be used to study the water management in situ in an operating fuel cell either to visualise the water accumulation in the gas distributors or to determine the water concentration profiles through the membrane and during operation.

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Section: The Former Studiessupporting

confidence: 71%

Neutron and X‐ray Scattering: Suitable Tools for Studying Ionomer Membranes

2005

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“…nique to identify structural organization within polymer systems and has been used extensively to study the nanostructure of Nafion membranes. [49][50][51][52] The random ionic clusters in Nafion act as a local cross-link and give rise to a local variation in cross-link density. Such network, on swelling in a low molecular weight solvent, exhibits competition between the osmotic pressure and the local elastic junction, resulting in local variation in polymer concentration.…”

Section: Nmr Studymentioning

confidence: 99%

Novel Organic−Inorganic Hybrids with Increased Water Retention for Elevated Temperature Proton Exchange Membrane Application

et al. 2008

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Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions? Contact the NRC Publications Archive team atPublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://doi.org/10.1021/cm801374hAccess and use of this website and the material on it are subject to the Terms and Conditions set forth at Novel organic−inorganic hybrids with increased water retention for elevated temperature proton exchange membrane application Mistry, Mayur K.; Choudhury, Namita Roy; Dutta, Naba K.; Knott, Robert; Shi, Zhiqing; Holdcroft, Steven http://nparc.cisti-icist.nrc-cnrc.gc.ca/fra/droits L'accès à ce site Web et l'utilisation de son contenu sont assujettis aux conditions présentées dans le site LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D'UTILISER CE SITE WEB. NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/eng/view/object/?id=8c195f29-9008-454b-8ea0-cf7782f3a619 http://nparc.cisti-icist.nrc-cnrc.gc.ca/fra/voir/objet/?id=8c195f29-9008-454b-8ea0-cf7782f3a619 Novel Organic-Inorganic Hybrids with Increased Water Retention for Elevated Temperature Proton Exchange Membrane ApplicationMayur K. Mistry, Namita Roy Choudhury,* Naba K. Dutta, Robert Knott, a Zhiqing Shi, b and Steven Holdcroft c Australia, Mawson Lakes Campus, Mawson Lakes, SA 5095, Australia ReceiVed June 3, 2008. ReVised Manuscript ReceiVed July 17, 2008 A new class of proton-conducting hybrid membranes have been developed using a combination of a solvent-directed infiltration method and sol-gel chemistry with a range of organofunctional silane and phosphate precursors. The phase-separated morphology of Nafion is used as a structure-directing template, which drives the inorganic component into the ionic clusters of the Nafion membrane. The kinetics of the sol-gel reactions were monitored using spectroscopic techniques. Photoacoustic Fourier transform infrared spectroscopy (PA-FTIR) confirms formation of Si-O-Si and Si-O-P bridges in the hybrid membranes, indicating silicate and phosphosilicate structures. The presence of the silicate/phosphosilicate network in the hybrid membranes enhances their thermal stability, thermomechanical properties, water r...

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“…These water domains are separated from the hydrophobic polymer matrix forming various shapes resulting in a two-phase nanostructure. [31][32][33][34][35][36][37][38][39][40][41][42] As the water-uptake increases, these water domains grow, and in some cases coalesce or change shape, 11,32,33,35,38,[43][44][45][46] causing continuous structural reorganization in the swollen polymer. Consequently, microscopic strain of the inter-domain spacing is higher than the macroscopic swelling strain.…”

Section: Equilibrium Water Uptakementioning

confidence: 99%

Understanding the Effects of Compression and Constraints on Water Uptake of Fuel-Cell Membranes

Kusoglu

Kienitz

Weber

2011

J. Electrochem. Soc.

118

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Accurate characterization of polymer-electrolyte fuel cells (PEFCs) requires understanding the impact of mechanical and electrochemical loads on cell components. An essential aspect of this relationship is the effect of compression on the polymer membrane's water-uptake behavior and transport properties. However, there is limited information on the impact of physical constraints on membrane properties. In this paper, we investigate both theoretically and experimentally how the water uptake of Nafion membrane changes under external compression loads. The swelling of a compressed membrane is modeled by modifying the swelling pressure in the polymer backbone which relies on the changes in the microscopic volume of the polymer. The model successfully predicts the water content of the compressed membrane measured through in-situ swelling-compression tests and neutron imaging. The results show that external mechanical loads could reduce the water content and conductivity of the membrane, especially at lower temperatures, higher humidities, and in liquid water. The modeling framework and experimental data provide valuable insight for the swelling and conductivity of constrained and compressed membranes, which are of interest in electrochemical devices such as batteries and fuel cells. † Current Address: W.L. Gore and Associates, 201 Airport Road, Elkton, MD USA ‡ Corresponding author. E-mail address: azweber@lbl.gov Tel: (510) 486-6308. * ECS Member. IntroductionIonomer membranes used in polymer-electrolyte-fuel-cell (PEFC) applications are always subjected to mechanical constraints to some extent due to cell design and clamping loads to reduce contact resistances and seal cells using compression seals. Furthermore, swelling of the membranes due to water uptake results in compressive stresses during cell operation. [1][2][3] Compression in the cell is known to influence membrane stresses, [2][3][4][5][6] transport in gas-diffusion layers (GDL), [7][8][9] and cell resistance. 10 However, the effect of the constraints and mechanical loads on the membrane's water-uptake behavior is yet to be determined due to the difficulty of such measurement. Moreover, due to the lack of the experimental data on the swelling behavior of constrained membranes, mathematical models on water uptake cannot be fully validated. In this work, we aim to investigate how the constraints on the membrane affect its water-uptake behavior and other water-dependent transport properties such as conductivity.In a PEFC, the extent to which the membrane is deformed depends on a number of factors including, but not limited to, geometry of the cell (e.g. land/channel ratio), thickness and stiffness of the cell components (e.g. bipolar plates, gas-diffusion layers (GDLs)), and operating conditions (e.g., humidity). Thus, stresses and pressures in the membrane are not uniform; they depend on location, time, and component material properties. In addition, the membrane itself is subjected to a combination of constraints and mechanical loads: (i) interfacial con...

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Phase separation in perfluorosulfonate ionomer membranes

Cited by 83 publications

References 8 publications

Neutron and X‐ray Scattering: Suitable Tools for Studying Ionomer Membranes

Neutron and X‐ray Scattering: Suitable Tools for Studying Ionomer Membranes

Novel Organic−Inorganic Hybrids with Increased Water Retention for Elevated Temperature Proton Exchange Membrane Application

Understanding the Effects of Compression and Constraints on Water Uptake of Fuel-Cell Membranes

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