1
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Zelovich T, Dekel DR, Tuckerman ME. Electrostatic Potential of Functional Cations as a Predictor of Hydroxide Diffusion Pathways in Nanoconfined Environments of Anion Exchange Membranes. J Phys Chem Lett 2024; 15:408-415. [PMID: 38179916 PMCID: PMC10801687 DOI: 10.1021/acs.jpclett.3c02800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 12/16/2023] [Accepted: 12/18/2023] [Indexed: 01/06/2024]
Abstract
Nanoconfined anion exchange membranes (AEMs) play a vital role in emerging electrochemical technologies. The ability to control dominant hydroxide diffusion pathways is an important goal in the design of nanoconfined AEMs. Such control can shorten hydroxide transport pathways between electrodes, reduce transport resistance, and enhance device performance. In this work, we propose an electrostatic potential (ESP) approach to explore the effect of the polymer electrolyte cation spacing on hydroxide diffusion pathways from a molecular perspective. By exploring cation ESP energy surfaces and validating outcomes through prior ab initio molecular dynamics simulations of nanoconfined AEMs, we find that we can achieve control over preferred hydroxide diffusion pathways by adjusting the cation spacing. The results presented in this work provide a unique and straightforward approach to predict preferential hydroxide diffusion pathways, enabling efficient design of highly conductive nanoconfined AEM materials for electrochemical technologies.
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Affiliation(s)
- Tamar Zelovich
- Department
of Chemistry, New York University (NYU), New York, New York 10003, United States
| | - Dario R. Dekel
- Wolfson
Department of Chemical Engineering, Technion
− Israel Institute of Technology, Haifa, 3200003, Israel
- Nancy
& Stephen Grand Technion Energy Program, Technion − Israel Institute of Technology, Haifa, 3200003, Israel
| | - Mark E. Tuckerman
- Department
of Chemistry, New York University (NYU), New York, New York 10003, United States
- Courant
Institute of Mathematical Sciences, New
York University (NYU), New York, New York 10012, United States
- NYU-ECNU
Center for Computational Chemistry at NYU Shanghai, 3663 Zhongshan Rd. North, Shanghai 200062, China
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2
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Abstract
Ion-containing polymers have continued to be an important research focus for several decades due to their use as an electrolyte in energy storage and conversion devices. Elucidation of connections between the mesoscopic structure and multiscale dynamics of the ions and solvent remains incompletely understood. Coarse-grained modeling provides an efficient approach for exploring the structural and dynamical properties of these soft materials. The unique physicochemical properties of such polymers are of broad interest. In this review, we summarize the current development and understanding of the structure-property relationship of ion-containing polymers and provide insights into the design of such materials determined from coarse-grained modeling and simulations accompanying significant advances in experimental strategies. We specifically concentrate on three types of ion-containing polymers: proton exchange membranes (PEMs), anion exchange membranes (AEMs), and polymerized ionic liquids (polyILs). We posit that insight into the similarities and differences in these materials will lead to guidance in the rational design of high-performance novel materials with improved properties for various power source technologies.
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Affiliation(s)
- Zhenghao Zhu
- Department of Chemical & Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Xubo Luo
- Department of Chemical & Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Stephen J Paddison
- Department of Chemical & Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
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3
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Primachenko ON, Kulvelis YV, Marinenko EA, Gofman IV, Lebedev VT, Kononova SV, Kuklin AI, Ivankov OI, Soloviov DV, Chenneviere A. Orientational uniaxial stretching of proton conducting perfluorinated membranes. J Appl Polym Sci 2022. [DOI: 10.1002/app.52229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Oleg N. Primachenko
- Institute of Macromolecular Compounds, Russian Academy of Sciences St. Petersburg Russia
| | - Yuri V. Kulvelis
- Petersburg Nuclear Physics Institute named by B.P. Konstantinov of National Research Centre “Kurchatov Institute” Gatchina Russia
| | - Elena A. Marinenko
- Institute of Macromolecular Compounds, Russian Academy of Sciences St. Petersburg Russia
| | - Iosif V. Gofman
- Institute of Macromolecular Compounds, Russian Academy of Sciences St. Petersburg Russia
| | - Vasily T. Lebedev
- Petersburg Nuclear Physics Institute named by B.P. Konstantinov of National Research Centre “Kurchatov Institute” Gatchina Russia
| | - Svetlana V. Kononova
- Institute of Macromolecular Compounds, Russian Academy of Sciences St. Petersburg Russia
| | - Alexander I. Kuklin
- Frank Laboratory of Neutron Physics Joint Institute for Nuclear Research Dubna Russia
- Moscow Institute of Physics and Technology Dolgoprudny Russia
| | - Oleksandr I. Ivankov
- Frank Laboratory of Neutron Physics Joint Institute for Nuclear Research Dubna Russia
| | - Dmytro V. Soloviov
- Frank Laboratory of Neutron Physics Joint Institute for Nuclear Research Dubna Russia
| | - Alexis Chenneviere
- Laboratoire Léon Brillouin UMR12 CEA‐CNRS CEA Saclay Gif sur Yvette Cedex France
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4
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Odess A, Cohen M, Li J, Dantus M, Zussman E, Freger V. Electrospun Ion-Conducting Composite Membrane with Buckling-Induced Anisotropic Through-Plane Conductivity. ACS APPLIED MATERIALS & INTERFACES 2021; 13:35700-35708. [PMID: 34292704 DOI: 10.1021/acsami.1c08087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Fuel cell (FC) is an attractive green alternative for today's fuel combustion systems. In common FCs, a polymer electrolyte membrane selectively conducts protons but blocks the passage of electrons and fuel. Nafion, the current benchmark membrane material, has a superior conductivity owing to unique morphology comprising randomly oriented elongated ionic nanochannels within its Teflon-like matrix. Channel orientation enhances Nafion conductivity, yet there has been no facile method to induce a stable alignment in the desired through-plane (TP) direction. Here, we report an approach based on dual electrospun Nafion-PVDF nanofiber composites that yields a stable TP alignment. It utilizes extreme thinness and strong inherent orientation within electrospun nanofibers, which is readily converted to TP alignment by plunging an electrospun nanofiber mat into a thin slit, resulting in nanofiber buckling and subsequent consolidation. Using TEM and SAXS, we demonstrate a pronounced and sustained TP ion channel orientation in prepared membranes, yielding a highly anisotropic swelling and conductivity exceeding that of bulk Nafion when normalized to Nafion content. The analysis also highlights the importance of PVDF as a stabilizing component, preserving orientation upon annealing, while a similarly prepared pure Nafion membrane loses anisotropy. The approach holds potential to advance the FC technology by overcoming current limitations of ionomeric membranes.
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Affiliation(s)
- Ariel Odess
- Wolfson Department of Chemical Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Matan Cohen
- Grand Technion Energy Program, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Jian Li
- Wolfson Department of Chemical Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Mauricio Dantus
- Russel Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Eyal Zussman
- Department of Mechanical Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Viatcheslav Freger
- Wolfson Department of Chemical Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
- Grand Technion Energy Program, Technion-Israel Institute of Technology, Haifa 3200003, Israel
- Russel Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
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5
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Kuo AT, Urata S, Nakabayashi K, Watabe H, Honmura S. Coarse-Grained Molecular Dynamics Simulation of Perfluorosulfonic Acid Polymer in Water–Ethanol Mixtures. Macromolecules 2021. [DOI: 10.1021/acs.macromol.0c02364] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- An-Tsung Kuo
- Innovative Technology Laboratories, AGC Inc., Yokohama 230-0045, Japan
| | - Shingo Urata
- Innovative Technology Laboratories, AGC Inc., Yokohama 230-0045, Japan
| | | | - Hiroyuki Watabe
- Materials Integration Laboratories, AGC Inc., Yokohama 230-0045, Japan
| | - Satoru Honmura
- Materials Integration Laboratories, AGC Inc., Yokohama 230-0045, Japan
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6
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Dumortier L, Mossa S. From Ionic Surfactants to Nafion through Convolutional Neural Networks. J Phys Chem B 2020; 124:8918-8927. [DOI: 10.1021/acs.jpcb.0c06172] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Loïc Dumortier
- X-ray Microspectroscopy and Imaging Group, Department of Chemistry, Ghent University, Krijgslaan 281/S12, B-9000 Gent, Belgium
| | - Stefano Mossa
- CEA, IRIG-MEM, Univ. Grenoble Alpes, 38000 Grenoble, France
- Institut Laue-Langevin,
BP 156, F-38042 Cedex 9 Grenoble, France
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7
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Feng C, Li Y, Qu K, Zhang Z, He P. Mechanical behavior of a hydrated perfluorosulfonic acid membrane at meso and nano scales. RSC Adv 2019; 9:9594-9603. [PMID: 35520728 PMCID: PMC9062152 DOI: 10.1039/c9ra00745h] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 03/15/2019] [Indexed: 01/13/2023] Open
Abstract
Perfluorosulfonic acid (PFSA) is widely used as the membrane material for proton-exchange membrane fuel cells, and its mechanical properties directly affect the stability and the life of the internal structure of the proton exchange membrane.
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Affiliation(s)
- Cong Feng
- College of Materials Science and Engineering
- Shanghai Key Lab of Metal Functional Materials
- Tongji University
- Shanghai 201804
- China
| | - Yan Li
- College of Materials Science and Engineering
- Shanghai Key Lab of Metal Functional Materials
- Tongji University
- Shanghai 201804
- China
| | - Kunnan Qu
- College of Materials Science and Engineering
- Shanghai Key Lab of Metal Functional Materials
- Tongji University
- Shanghai 201804
- China
| | - Zhiming Zhang
- School of Automotive Studies
- Tongji University
- Shanghai 201804
- China
| | - Pengfei He
- School of Aerospace Engineering and Applied Mechanics
- Tongji University
- Shanghai 200092
- China
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8
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Vishnyakov A, Mao R, Lee MT, Neimark AV. Coarse-grained model of nanoscale segregation, water diffusion, and proton transport in Nafion membranes. J Chem Phys 2018; 148:024108. [PMID: 29331134 DOI: 10.1063/1.4997401] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present a coarse-grained model of the acid form of Nafion membrane that explicitly includes proton transport. This model is based on a soft-core bead representation of the polymer implemented into the dissipative particle dynamics (DPD) simulation framework. The proton is introduced as a separate charged bead that forms dissociable Morse bonds with water beads. Morse bond formation and breakup artificially mimics the Grotthuss hopping mechanism of proton transport. The proposed DPD model is parameterized to account for the specifics of the conformations and flexibility of the Nafion backbone and sidechains; it treats electrostatic interactions in the smeared charge approximation. The simulation results qualitatively, and in many respects quantitatively, predict the specifics of nanoscale segregation in the hydrated Nafion membrane into hydrophobic and hydrophilic subphases, water diffusion, and proton mobility. As the hydration level increases, the hydrophilic subphase exhibits a percolation transition from a collection of isolated water clusters to a 3D network of pores filled with water embedded in the hydrophobic matrix. The segregated morphology is characterized in terms of the pore size distribution with the average size growing with hydration from ∼1 to ∼4 nm. Comparison of the predicted water diffusivity with the experimental data taken from different sources shows good agreement at high and moderate hydration and substantial deviation at low hydration, around and below the percolation threshold. This discrepancy is attributed to the dynamic percolation effects of formation and rupture of merging bridges between the water clusters, which become progressively important at low hydration, when the coarse-grained model is unable to mimic the fine structure of water network that includes singe molecule bridges. Selected simulations of water diffusion are performed for the alkali metal substituted membrane which demonstrate the effects of the counter-ions on membrane self-assembly and transport. The hydration dependence of the proton diffusivity reproduces semi-qualitatively the trend of the diverse experimental data, showing a sharp decrease around the percolation threshold. Overall, the proposed model opens up an opportunity to study self-assembly and water and proton transport in polyelectrolytes using computationally efficient DPD simulations, and, with further refinement, it may become a practical tool for theory informed design and optimization of perm-selective and ion-conducting membranes with improved properties.
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Affiliation(s)
- Aleksey Vishnyakov
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, 98 Brett Road, Piscataway, New Jersey 08854-8058, USA
| | - Runfang Mao
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, 98 Brett Road, Piscataway, New Jersey 08854-8058, USA
| | - Ming-Tsung Lee
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, 98 Brett Road, Piscataway, New Jersey 08854-8058, USA
| | - Alexander V Neimark
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, 98 Brett Road, Piscataway, New Jersey 08854-8058, USA
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9
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Exploring the effect of pendent side chain length on the structural and mechanical properties of hydrated perfluorosulfonic acid polymer membranes by molecular dynamics simulation. POLYMER 2018. [DOI: 10.1016/j.polymer.2018.05.033] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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10
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Berrod Q, Hanot S, Guillermo A, Mossa S, Lyonnard S. Water sub-diffusion in membranes for fuel cells. Sci Rep 2017; 7:8326. [PMID: 28827621 PMCID: PMC5567110 DOI: 10.1038/s41598-017-08746-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 07/12/2017] [Indexed: 11/09/2022] Open
Abstract
We investigate the dynamics of water confined in soft ionic nano-assemblies, an issue critical for a general understanding of the multi-scale structure-function interplay in advanced materials. We focus in particular on hydrated perfluoro-sulfonic acid compounds employed as electrolytes in fuel cells. These materials form phase-separated morphologies that show outstanding proton-conducting properties, directly related to the state and dynamics of the absorbed water. We have quantified water motion and ion transport by combining Quasi Elastic Neutron Scattering, Pulsed Field Gradient Nuclear Magnetic Resonance, and Molecular Dynamics computer simulation. Effective water and ion diffusion coefficients have been determined together with their variation upon hydration at the relevant atomic, nanoscopic and macroscopic scales, providing a complete picture of transport. We demonstrate that confinement at the nanoscale and direct interaction with the charged interfaces produce anomalous sub-diffusion, due to a heterogeneous space-dependent dynamics within the ionic nanochannels. This is irrespective of the details of the chemistry of the hydrophobic confining matrix, confirming the statistical significance of our conclusions. Our findings turn out to indicate interesting connections and possibilities of cross-fertilization with other domains, including biophysics. They also establish fruitful correspondences with advanced topics in statistical mechanics, resulting in new possibilities for the analysis of Neutron scattering data.
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Affiliation(s)
- Quentin Berrod
- LLB, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191, Gif-sur-Yvette, France
- Lawrence Berkeley National Laboratory, Energy Storage Group, 94720, Berkeley, USA
| | - Samuel Hanot
- Institut Laue-Langevin, 71 Avenue des Martyrs, CS, 20156 - 38042, Grenoble, France
- Unité de Bioinformatique Structurale, Institut Pasteur, Paris, France
- UMR 3528, CNRS, Paris, France
| | - Armel Guillermo
- Univ. Grenoble Alpes, CEA, CNRS, INAC, SYMMES, F-38000, Grenoble, France
| | - Stefano Mossa
- Univ. Grenoble Alpes, CEA, CNRS, INAC, SYMMES, F-38000, Grenoble, France.
| | - Sandrine Lyonnard
- Univ. Grenoble Alpes, CEA, CNRS, INAC, SYMMES, F-38000, Grenoble, France.
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11
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Allahyarov E, Löwen H, Taylor PL. Simulation Study of Ion Diffusion in Charged Nanopores with Anchored Terminal Groups. Electrochim Acta 2017. [DOI: 10.1016/j.electacta.2017.04.158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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12
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Abstract
In this comprehensive review, recent progress and developments on perfluorinated sulfonic-acid (PFSA) membranes have been summarized on many key topics. Although quite well investigated for decades, PFSA ionomers' complex behavior, along with their key role in many emerging technologies, have presented significant scientific challenges but also helped create a unique cross-disciplinary research field to overcome such challenges. Research and progress on PFSAs, especially when considered with their applications, are at the forefront of bridging electrochemistry and polymer (physics), which have also opened up development of state-of-the-art in situ characterization techniques as well as multiphysics computation models. Topics reviewed stem from correlating the various physical (e.g., mechanical) and transport properties with morphology and structure across time and length scales. In addition, topics of recent interest such as structure/transport correlations and modeling, composite PFSA membranes, degradation phenomena, and PFSA thin films are presented. Throughout, the impact of PFSA chemistry and side-chain is also discussed to present a broader perspective.
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Affiliation(s)
- Ahmet Kusoglu
- Energy Conversion Group, Energy Technologies Area, Lawrence Berkeley National Laboratory , 1 Cyclotron Road, MS70-108B, Berkeley, California 94720, United States
| | - Adam Z Weber
- Energy Conversion Group, Energy Technologies Area, Lawrence Berkeley National Laboratory , 1 Cyclotron Road, MS70-108B, Berkeley, California 94720, United States
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13
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Watanabe T, Tanaka M, Kawakami H. Fabrication and electrolyte characterization of uniaxially-aligned anion conductive polymer nanofibers. NANOSCALE 2016; 8:19614-19619. [PMID: 27845469 DOI: 10.1039/c6nr07828a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We report the anion transport properties of anion conductive polymer nanofibers fabricated using an electrospinning method. The aligned nanofibers were prepared to evaluate the anion conductivity of the nanofibers. The aligned nanofibers had 10-15 times higher conductivity (up to 160 mS cm-1 at 90 °C and 95%RH) and lower activation energy (23-25 kJ mol-1) than the corresponding membranes, even though the nanofibers showed lower water uptake than the corresponding membranes. The anion conductivity measurement of nanofibers with different IEC values and anion species revealed that the dependency of anion conductivity on these factors was smaller in the nanofibers than in the corresponding membranes. These results indicate that effective ion transport pathways were formed in the nanofibers due to the phase separation and the polymer chain orientation along the nanofiber axis. These nanofibers are expected to be useful for future applications in alkaline fuel cells, air batteries, and other energy- and environment-related devices regardless of the ion species.
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Affiliation(s)
- Tsukasa Watanabe
- Department of Applied Chemistry, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan.
| | - Manabu Tanaka
- Department of Applied Chemistry, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan.
| | - Hiroyoshi Kawakami
- Department of Applied Chemistry, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan.
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14
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Hanot S, Lyonnard S, Mossa S. Sub-diffusion and population dynamics of water confined in soft environments. NANOSCALE 2016; 8:3314-3325. [PMID: 26690685 DOI: 10.1039/c5nr05853h] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We have studied by using molecular dynamics computer simulations the dynamics of water confined in ionic surfactant phases, ranging from well ordered lamellar structures to micelles at low and high water loading, respectively. We have analysed in depth the main dynamical features in terms of mean-squared displacements and intermediate scattering functions, and found clear evidence of sub-diffusive behaviour. We have identified water molecules lying at the charged interface with the hydrophobic confining matrix as the main factor responsible for this unusual feature, and given a comprehensive picture of dynamics based on a very precise analysis of lifetimes at the interface. We conclude by providing, for the first time to our knowledge, a unique framework for rationalizing the existence of important dynamical heterogeneities in fluids adsorbed in soft confining environments.
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Affiliation(s)
- Samuel Hanot
- Institut Laue-Langevin, 71 Avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9, France.
| | - Sandrine Lyonnard
- Univ. Grenoble Alpes, INAC-SPRAM, F-38000 Grenoble, France. and CNRS, INAC-SPRAM, F-38000 Grenoble, France and CEA, INAC-SPRAM, F-38000 Grenoble, France.
| | - Stefano Mossa
- Univ. Grenoble Alpes, INAC-SPRAM, F-38000 Grenoble, France. and CNRS, INAC-SPRAM, F-38000 Grenoble, France and CEA, INAC-SPRAM, F-38000 Grenoble, France.
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15
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Kulvelis Y, Ivanchev SS, Primachenko ON, Lebedev VT, Marinenko EA, Ivanova IN, Kuklin AI, Ivankov OI, Soloviov DV. Structure and property optimization of perfluorinated short side chain membranes for hydrogen fuel cells using orientational stretching. RSC Adv 2016. [DOI: 10.1039/c6ra23445c] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Stretching of membranes with low molecular weight makes structure rearrangement according to neutron scattering data on D2O-filled membranes.
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Affiliation(s)
- Yu. V. Kulvelis
- Neutron Researches Department
- B.P. Konstantinov Petersburg Nuclear Physics Institute
- National Research Centre “Kurchatov Institute”
- Gatchina
- Russia
| | - S. S. Ivanchev
- St. Petersburg Department of Boreskov Institute of Catalysis
- Siberian Branch of Russian Academy of Sciences
- St. Petersburg
- Russia
| | - O. N. Primachenko
- St. Petersburg Department of Boreskov Institute of Catalysis
- Siberian Branch of Russian Academy of Sciences
- St. Petersburg
- Russia
| | - V. T. Lebedev
- Neutron Researches Department
- B.P. Konstantinov Petersburg Nuclear Physics Institute
- National Research Centre “Kurchatov Institute”
- Gatchina
- Russia
| | - E. A. Marinenko
- St. Petersburg Department of Boreskov Institute of Catalysis
- Siberian Branch of Russian Academy of Sciences
- St. Petersburg
- Russia
| | - I. N. Ivanova
- Neutron Researches Department
- B.P. Konstantinov Petersburg Nuclear Physics Institute
- National Research Centre “Kurchatov Institute”
- Gatchina
- Russia
| | - A. I. Kuklin
- Joint Institute for Nuclear Research
- Dubna
- Russia
- Moscow Institute of Physics and Technology
- Dolgoprudny
| | - O. I. Ivankov
- Joint Institute for Nuclear Research
- Dubna
- Russia
- Moscow Institute of Physics and Technology
- Dolgoprudny
| | - D. V. Soloviov
- Joint Institute for Nuclear Research
- Dubna
- Russia
- Moscow Institute of Physics and Technology
- Dolgoprudny
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16
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Allahyarov E, Taylor PL, Löwen H. Enhanced ionic diffusion in ionomer-filled nanopores. J Chem Phys 2015; 143:243126. [DOI: 10.1063/1.4935114] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Affiliation(s)
- Elshad Allahyarov
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine Universität Düsseldorf, Universitätstrasse 1, 40225 Düsseldorf, Germany
- Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, Ohio 44106-7202, USA
- Theoretical Department, Joint Institute for High Temperatures, Russian Academy of Sciences (IVTAN), 13/19 Izhorskaya Street, Moscow 125412, Russia
- International Research Centre, Baku State University, Baku, Azerbaijan
| | - Philip L. Taylor
- Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106-7079, USA
| | - Hartmut Löwen
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine Universität Düsseldorf, Universitätstrasse 1, 40225 Düsseldorf, Germany
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17
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18
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19
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Hink S, Henkensmeier D, Jang JH, Kim HJ, Han J, Nam SW. Reduced In-Plane Swelling of Nafion by a Biaxial Modification Process. MACROMOL CHEM PHYS 2015. [DOI: 10.1002/macp.201500063] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Steffen Hink
- Korea Institute of Science and Technology; Fuel Cell Research Center; Hwarangno 14-gil 5 136-791 Seoul Republic of Korea
| | - Dirk Henkensmeier
- Korea Institute of Science and Technology; Fuel Cell Research Center; Hwarangno 14-gil 5 136-791 Seoul Republic of Korea
- Energy and Environmental Engineering University of Science and Technology; 217 Gajeongro Yuseonggu Daejeon 305-350 Republic of Korea
| | - Jong Hyun Jang
- Korea Institute of Science and Technology; Fuel Cell Research Center; Hwarangno 14-gil 5 136-791 Seoul Republic of Korea
- Green School; Korea University; Seoul 136-713 Republic of Korea
| | - Hyoung-Juhn Kim
- Korea Institute of Science and Technology; Fuel Cell Research Center; Hwarangno 14-gil 5 136-791 Seoul Republic of Korea
| | - Jonghee Han
- Korea Institute of Science and Technology; Fuel Cell Research Center; Hwarangno 14-gil 5 136-791 Seoul Republic of Korea
| | - Suk-Woo Nam
- Korea Institute of Science and Technology; Fuel Cell Research Center; Hwarangno 14-gil 5 136-791 Seoul Republic of Korea
- Green School; Korea University; Seoul 136-713 Republic of Korea
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20
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Hanot S, Lyonnard S, Mossa S. Water confined in self-assembled ionic surfactant nano-structures. SOFT MATTER 2015; 11:2469-2478. [PMID: 25674917 DOI: 10.1039/c5sm00179j] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present a coarse-grained model for ionic surfactants in explicit aqueous solutions, and study by computer simulation both the impact of water content on the morphology of the system, and the consequent effect of the formed interfaces on the structural features of the absorbed fluid. On increasing the hydration level under ambient conditions, the model exhibits a series of three distinct phases: lamellar, cylindrical and micellar. We characterize the different structures in terms of diffraction patterns and neutron scattering static structure factors. We demonstrate that the rate of variation of the nano-metric sizes of the self-assembled water domains shows peculiar changes in the different phases. We also analyse in depth the structure of the water/confining matrix interfaces, the implications of their tunable degree of curvature, and the properties of water molecules in different restricted environments. Finally, we compare our results with experimental data and their impact on a wide range of important scientific and technological domains, where the behavior of water at the interface with soft materials is crucial.
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Affiliation(s)
- Samuel Hanot
- Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9, France
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21
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Pérez-Maciá MA, Curcó D, Bringué R, Iborra M, Alemán C. Atomistic simulations of the structure of highly crosslinked sulfonated poly(styrene-co-divinylbenzene) ion exchange resins. SOFT MATTER 2015; 11:2251-2267. [PMID: 25651925 DOI: 10.1039/c4sm02417f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The microscopic structures of highly crosslinked sulfonated poly(styrene-co-divinylbenzene) resins have been modeled by generating atomistic microstructures using stochastic-like algorithms, which are subsequently relaxed using molecular dynamics. Two different generation algorithms have been tested. The relaxation of the microstructures generated by the first algorithm, which is based on a homogeneous construction of the resin, leads to a significant overestimation of the experimental density as well as to an unsatisfactory description of the porosity. In contrast, the generation approach that combines algorithms for the heterogeneous growing and branching of the chains enables the formation of crosslinks with different topologies. In particular, the intrinsic heterogeneity observed in these resins is efficiently reproduced when the topological loops, which are defined by two or more crosslinks closing a cycle, are present in their microscopic description. Thus, the apparent density, porosity and pore volume estimated using microstructures with these topological loops, called super-crosslinks, are in very good agreement with the experimental results. Although the backbone dihedral angle distribution of the generated and relaxed models is not influenced by the topology, the number and type of crosslinks affect the medium- and long-range atomic disposition of the backbone atoms and the distribution of sulfonic groups. An analysis of the distribution of the local density indicates that super-crosslinks are responsible for the heterogeneous homogenization observed during the MD relaxation. Finally the π-π stacking interactions have been analyzed. Results indicate that those in which the two rings adopt a T-shaped disposition are considerably more abundant as compared to those with the co-facially oriented rings, independently of the resin topology.
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Affiliation(s)
- María A Pérez-Maciá
- Departament d'Enginyeria Química, Facultat de Química, Universitat de Barcelona, Martí i Franqués 1, Barcelona E-08028, Spain.
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22
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Takemori R, Ito G, Tanaka M, Kawakami H. Ultra-high proton conduction in electrospun sulfonated polyimide nanofibers. RSC Adv 2014. [DOI: 10.1039/c4ra02155j] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Uniaxially-aligned sulfonated polyimide nanofibers fabricated by an electrospinning method showed ultra-high proton conductivities due to molecular orientation in the nanofibers.
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Affiliation(s)
- Ryouhei Takemori
- Department of Applied Chemistry
- Tokyo Metropolitan University
- Hachioji, Japan
| | - Genki Ito
- Department of Applied Chemistry
- Tokyo Metropolitan University
- Hachioji, Japan
| | - Manabu Tanaka
- Department of Applied Chemistry
- Tokyo Metropolitan University
- Hachioji, Japan
| | - Hiroyoshi Kawakami
- Department of Applied Chemistry
- Tokyo Metropolitan University
- Hachioji, Japan
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23
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Klein M, Perrin JC, Leclerc S, Guendouz L, Dillet J, Lottin O. Anisotropy of Water Self-Diffusion in a Nafion Membrane under Traction. Macromolecules 2013. [DOI: 10.1021/ma401511t] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Mathieu Klein
- Université
de Lorraine, LEMTA, UMR7563, Vandoeuvre-lès-Nancy, F-54500, France
- CNRS, LEMTA, UMR7563, Vandoeuvre-lès-Nancy, F-54500, France
| | - Jean-Christophe Perrin
- Université
de Lorraine, LEMTA, UMR7563, Vandoeuvre-lès-Nancy, F-54500, France
- CNRS, LEMTA, UMR7563, Vandoeuvre-lès-Nancy, F-54500, France
| | - Sébastien Leclerc
- Université
de Lorraine, LEMTA, UMR7563, Vandoeuvre-lès-Nancy, F-54500, France
- CNRS, LEMTA, UMR7563, Vandoeuvre-lès-Nancy, F-54500, France
| | - Laouès Guendouz
- Institut
Jean-Lamour, UMR 7198, CNRS, Université de Lorraine, Vandoeuvre-lès-Nancy, F- 54500, France
| | - Jérôme Dillet
- Université
de Lorraine, LEMTA, UMR7563, Vandoeuvre-lès-Nancy, F-54500, France
- CNRS, LEMTA, UMR7563, Vandoeuvre-lès-Nancy, F-54500, France
| | - Olivier Lottin
- Université
de Lorraine, LEMTA, UMR7563, Vandoeuvre-lès-Nancy, F-54500, France
- CNRS, LEMTA, UMR7563, Vandoeuvre-lès-Nancy, F-54500, France
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24
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Komarov PV, Khalatur PG, Khokhlov AR. Large-scale atomistic and quantum-mechanical simulations of a Nafion membrane: Morphology, proton solvation and charge transport. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2013; 4:567-87. [PMID: 24205452 PMCID: PMC3817934 DOI: 10.3762/bjnano.4.65] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 08/27/2013] [Indexed: 05/29/2023]
Abstract
Atomistic and first-principles molecular dynamics simulations are employed to investigate the structure formation in a hydrated Nafion membrane and the solvation and transport of protons in the water channel of the membrane. For the water/Nafion systems containing more than 4 million atoms, it is found that the observed microphase-segregated morphology can be classified as bicontinuous: both majority (hydrophobic) and minority (hydrophilic) subphases are 3D continuous and organized in an irregular ordered pattern, which is largely similar to that known for a bicontinuous double-diamond structure. The characteristic size of the connected hydrophilic channels is about 25-50 Å, depending on the water content. A thermodynamic decomposition of the potential of mean force and the calculated spectral densities of the hindered translational motions of cations reveal that ion association observed with decreasing temperature is largely an entropic effect related to the loss of low-frequency modes. Based on the results from the atomistic simulation of the morphology of Nafion, we developed a realistic model of ion-conducting hydrophilic channel within the Nafion membrane and studied it with quantum molecular dynamics. The extensive 120 ps-long density functional theory (DFT)-based simulations of charge migration in the 1200-atom model of the nanochannel consisting of Nafion chains and water molecules allowed us to observe the bimodality of the van Hove autocorrelation function, which provides the direct evidence of the Grotthuss bond-exchange (hopping) mechanism as a significant contributor to the proton conductivity.
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Affiliation(s)
- Pavel V Komarov
- Institute of Organoelement Compounds, RAS, Moscow 119991, Russia
- Department of Theoretical Physics, Tver State University, Tver 170002, Russia
| | - Pavel G Khalatur
- Institute of Organoelement Compounds, RAS, Moscow 119991, Russia
- Institute for Advanced Energy Related Nanomaterials, Ulm University, Ulm D-89069, Germany
| | - Alexei R Khokhlov
- Institute of Organoelement Compounds, RAS, Moscow 119991, Russia
- Institute for Advanced Energy Related Nanomaterials, Ulm University, Ulm D-89069, Germany
- Physics Department, Moscow State University, Moscow 119991, Russia
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25
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26
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Allahyarov E, Taylor PL, Löwen H. Simulation study of poled low-water ionomers with different architectures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:455102. [PMID: 21975381 DOI: 10.1088/0953-8984/23/45/455102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The role of the ionomer architecture in the formation of ordered structures in poled membranes is investigated by molecular dynamics computer simulations. It is shown that the length of the sidechain L(s) controls both the areal density of cylindrical aggregates N(c) and the diameter of these cylinders in the poled membrane. The backbone segment length L(b) tunes the average diameter D(s) of cylindrical clusters and the average number of sulfonates N(s) in each cluster. A simple empirical formula is noted for the dependence of the number density of induced rod-like aggregates on the sidechain length L(s) within the parameter range considered in this study.
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Affiliation(s)
- Elshad Allahyarov
- Department of Physics, Case Western Reserve University, Cleveland, OH 44106, USA
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27
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Ilhan MA, Spohr E. Hydrogen bonding in narrow protonated polymer electrolyte pores. J Electroanal Chem (Lausanne) 2011. [DOI: 10.1016/j.jelechem.2011.03.035] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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28
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Park JK, Li J, Divoux GM, Madsen LA, Moore RB. Oriented Morphology and Anisotropic Transport in Uniaxially Stretched Perfluorosulfonate Ionomer Membranes. Macromolecules 2011. [DOI: 10.1021/ma200865p] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Jong Keun Park
- Department of Chemistry and Macromolecules and Interfaces Institute, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
| | - Jing Li
- International Flavors and Fragrances, Union Beach, New Jersey 07735, United States
| | - Gilles M. Divoux
- Department of Chemistry and Macromolecules and Interfaces Institute, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
| | - Louis A. Madsen
- Department of Chemistry and Macromolecules and Interfaces Institute, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
| | - Robert B. Moore
- Department of Chemistry and Macromolecules and Interfaces Institute, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
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29
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Li J, Park JK, Moore RB, Madsen LA. Linear coupling of alignment with transport in a polymer electrolyte membrane. NATURE MATERIALS 2011; 10:507-511. [PMID: 21685901 DOI: 10.1038/nmat3048] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Accepted: 05/11/2011] [Indexed: 05/30/2023]
Abstract
Polymer electrolyte membranes (PEMs) selectively transport ions and polar molecules in a robust yet formable solid support. Tailored PEMs allow for devices such as solid-state batteries,'artificial muscle' actuators and reverse-osmosis water purifiers. Understanding how PEM structure and morphology relate to mobile species transport presents a challenge for designing next-generation materials. Material length scales from subnanometre to 1 μm influence bulk properties such as ion conductivity and water transport. Here we employ multi-axis pulsed-field-gradient NMR to measure diffusion anisotropy, and (2)H NMR spectroscopy and synchrotron small-angle X-ray scattering to probe orientational order as a function of water content and of membrane stretching. Strikingly, transport anisotropy linearly depends on the degree of alignment, signifying that membrane stretching affects neither the nanometre-scale channel dimensions nor the defect structure,causing only domain reorientation. The observed reorientation of anisotropic domains without perturbation of the inherent nematic-like domain character parallels the behaviour of nematic elastomers, promises tailored membrane conduction and potentially allows understanding of tunable shape-memory effects in PEM materials. This quantitative understanding will drive PEM design efforts towards optimal membrane transport, thus enabling more efficient polymeric batteries, fuel cells, mechanical actuators and water purification.
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Affiliation(s)
- Jing Li
- Department of Chemistry and Macromolecules and Interfaces Institute, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA
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30
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Ilhan MA, Spohr E. Ab initio molecular dynamics of proton networks in narrow polymer electrolyte pores. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:234104. [PMID: 21613694 DOI: 10.1088/0953-8984/23/23/234104] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
It is well established that proton conductivity in fuel cell membrane materials such as Nafion decreases strongly with decreasing water content. Proton transport in almost dry membranes is thought to proceed through narrow channels. In the present work we investigate proton structure and dynamics in two narrow cylindrical pores, which differ by their radius and the spacing of SO(3)H groups inside the channel. Pores are modelled through eight CF(3)CF(3) and four CF(3)SO(3)H entities in a helical arrangement. The water content λ (the ratio between the number of water molecules and the number of sulfonic acid groups) in the pores varies between 2.5 and 4.5. We observe a transition from the undissociated acid at very low λ through more or less localized H(3)O(+) entities to more delocalized H(5)O(2)(+) entities for the investigated range of λ. In the narrower pore, where S-S distances vary in a more favourable range (between 6 and 8.5 Å) than in the wider pore, we find that the molecular mobility is significantly higher, even at a rather high density of water molecules inside the pore.
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Affiliation(s)
- Mehmet A Ilhan
- Lehrstuhl für Theoretische Chemie, Universität Duisburg-Essen, D-45141 Essen, Germany
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31
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Allahyarov E, Taylor PL, Löwen H. A simulation study of field-induced proton-conduction pathways in dry ionomers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:234105. [PMID: 21613717 DOI: 10.1088/0953-8984/23/23/234105] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The morphological changes that can be induced in a dry ionomer by application of a strong electric field have been studied by means of computer simulation. The internal energy of the membrane at first slowly decreases with increasing field, but then rapidly increases after a certain threshold field is reached. This effect is interpreted as the reorganization of interacting head group dipoles in response to the external perturbation. The resulting morphology contains continuous channels of hydrophilic material capable of facilitating proton conduction. Upon removal of the poling field, the system does not return to its original morphology, but retains the anisotropic structure of the poled material. The poled structure appears to be thermodynamically stable, as confirmed by calculations of the Helmholtz energy of the original and poled samples.
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Affiliation(s)
- Elshad Allahyarov
- Department of Physics, Case Western Reserve University, Cleveland, OH 44106, USA
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32
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Allahyarov E, Taylor PL. Simulation study of the equilibrium morphology in ionomers with different architectures. ACTA ACUST UNITED AC 2011. [DOI: 10.1002/polb.22191] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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33
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Bertran O, Curcó D, Torras J, Ferreira CA, Alemán C. Field-Induced Transport in Sulfonated Poly(styrene-co-divinylbenzene) Membranes. Macromolecules 2010. [DOI: 10.1021/ma102500w] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Oscar Bertran
- Departament de Física Aplicada, EEI, Universitat Politècnica de Catalunya, Pça. Rei 15, 08700 Igualada, Spain
| | - David Curcó
- Department d’Enginyeria Química, Facultat de Química, Universitat de Barcelona, Martí Franques 1, Barcelona E-08028, Spain
| | - Juan Torras
- Departament d’Enginyeria Química, EEI, Universitat Politècnica de Catalunya, Pça. Rei 15, 08700 Igualada, Spain
| | - Carlos A. Ferreira
- Universidade Federal do Rio Grande do Sul, PPGEM, Av. Bento Gonçalves, 9500, setor 4, prédio 74, Cep. 91501-970, Porto Alegre, RS, Brazil
| | - Carlos Alemán
- Departament d’Enginyeria Química, E. T. S. d’Enginyers Industrials, Universitat Politècnica de Catalunya, Diagonal 647, 08028 Barcelona, Spain
- Center for Research in Nano-Engineering, Universitat Politècnica de Catalunya, Campus Sud, Edifici C’, C/Pasqual i Vila s/n, Barcelona E-08028, Spain
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34
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Allahyarov E, Taylor PL, Löwen H. Simulation study of field-induced morphological changes in a proton-conducting ionomer. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 81:031805. [PMID: 20365763 DOI: 10.1103/physreve.81.031805] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Revised: 01/24/2010] [Indexed: 05/29/2023]
Abstract
A simulation study was made of the effects of strong electric fields on the morphology of a Nafion-like ionomer at various levels of hydration. The results of united-atom molecular-dynamics computations showed a self-organization of the side chain terminal groups into cylindrical clusters. The walls of these clusters contain the sulfonate dipoles, while the interior holds the majority of the water molecules. These cylindrical structures then align to form an hexatic array aligned along the direction of the applied electric field. The hexatic morphology persists after the removal of the field. A calculation by means of the Kirkwood coupling parameter method shows the Helmholtz free energy of the hexatic morphology of the poled membrane to be lower than that of the initial isotropic material, even in the absence of the applied field.
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Affiliation(s)
- Elshad Allahyarov
- Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106, USA
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35
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Shao C, Yan L, Ji X, Zhu S. Intermolecular momentum transfer in poly(perfluorosulfonic acid) membrane hydrated by aqueous solution of methanol: A molecular dynamics simulation study. J Chem Phys 2010; 131:224901. [PMID: 20001078 DOI: 10.1063/1.3271829] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Intermolecular momentum transfer in methanol-water mixture solvated poly(perfluoro-sulfonic acid) membrane is studied in terms of center of mass velocity cross-correlation functions between molecular mass centers in their first coordination shells based on molecular dynamics simulations. Moreover, the center of mass velocity cross-correlation functions are also decomposed into longitudinal and transversal contributions. The fastest momentum transfer is observed between hydronium cation and water molecule due to the strong hydrogen bond interaction. The center of mass velocity cross-correlation functions reach peak value in about 36 fs, corresponding to a single collision with a neighboring molecule. For the momentum transfer between the water molecule and methanol molecule, the peaking time is 70 fs or about twice of that between hydronium cation and water molecule. Oscillation of the center of mass velocity cross-correlation functions between hydronium cation and water molecule is also observed due to the cage effect in their equilibrium positions.
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Affiliation(s)
- Changle Shao
- Department of Chemistry, College of Sciences, Shanghai University, 99 Shangda Road, Shanghai 200444, China
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36
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Knox CK, Voth GA. Probing Selected Morphological Models of Hydrated Nafion Using Large-Scale Molecular Dynamics Simulations. J Phys Chem B 2010; 114:3205-18. [DOI: 10.1021/jp9112409] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Craig K. Knox
- Departments of Chemistry and Chemical Engineering and Center for Biophysical Modeling and Simulation, Room 2020, 315 South 1400 East, University of Utah, Salt Lake City, Utah 84112-0850
| | - Gregory A. Voth
- Departments of Chemistry and Chemical Engineering and Center for Biophysical Modeling and Simulation, Room 2020, 315 South 1400 East, University of Utah, Salt Lake City, Utah 84112-0850
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37
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Felice C, Ye S, Qu D. Nafion−Montmorillonite Nanocomposite Membrane for the Effective Reduction of Fuel Crossover. Ind Eng Chem Res 2010. [DOI: 10.1021/ie901600a] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Christine Felice
- Department of Chemistry, University of Massachusetts Boston, Boston, Massachusetts 01225
| | - Stanley Ye
- Department of Chemistry, University of Massachusetts Boston, Boston, Massachusetts 01225
| | - Deyang Qu
- Department of Chemistry, University of Massachusetts Boston, Boston, Massachusetts 01225
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38
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Allahyarov E, Taylor PL, Löwen H. Simulation study of sulfonate cluster swelling in ionomers. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 80:061802. [PMID: 20365182 DOI: 10.1103/physreve.80.061802] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Indexed: 05/29/2023]
Abstract
We have performed simulations to study how increasing humidity affects the structure of Nafion-like ionomers under conditions of low sulfonate concentration and low humidity. At the onset of membrane hydration, the clusters split into smaller parts. These subsequently swell, but then maintain constant the number of sulfonates per cluster. We find that the distribution of water in low-sulfonate membranes depends strongly on the sulfonate concentration. For a relatively low sulfonate concentration, nearly all the side-chain terminal groups are within cluster formations, and the average water loading per cluster matches the water content of membrane. However, for a relatively higher sulfonate concentration the water-to-sulfonate ratio becomes nonuniform. The clusters become wetter, while the intercluster bridges become drier. We note the formation of unusual shells of water-rich material that surround the sulfonate clusters.
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Affiliation(s)
- Elshad Allahyarov
- Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106, USA
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39
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Allahyarov E, Taylor PL. Predicted electric-field-induced hexatic structure in an ionomer membrane. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 80:020801. [PMID: 19792066 DOI: 10.1103/physreve.80.020801] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Indexed: 05/28/2023]
Abstract
Coarse-grained molecular-dynamics simulations were used to study the morphological changes induced in a Nafion-like ionomer by the imposition of a strong electric field. We observe the formation of structures aligned along the direction of the applied field. The polar head groups of the ionomer sidechains aggregate into clusters, which then form rodlike formations which assemble into a hexatic array aligned with the direction of the field. Occasionally these lines of sulfonates and protons form a helical structure. Upon removal of the electric field, the hexatic array of rodlike structures persists and has a lower calculated free energy than the original isotropic morphology.
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Affiliation(s)
- Elshad Allahyarov
- Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106, USA
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40
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Spry DB, Fayer MD. Proton Transfer and Proton Concentrations in Protonated Nafion Fuel Cell Membranes. J Phys Chem B 2009; 113:10210-21. [DOI: 10.1021/jp9036777] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- D. B. Spry
- Department of Chemistry, Stanford University, Stanford, California 94305
| | - M. D. Fayer
- Department of Chemistry, Stanford University, Stanford, California 94305
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