1
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Jinnouchi R, Minami S, Karsai F, Verdi C, Kresse G. Proton Transport in Perfluorinated Ionomer Simulated by Machine-Learned Interatomic Potential. J Phys Chem Lett 2023; 14:3581-3588. [PMID: 37018477 DOI: 10.1021/acs.jpclett.3c00293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Polymers are a class of materials that are highly challenging to deal with using first-principles methods. Here, we present an application of machine-learned interatomic potentials to predict structural and dynamical properties of dry and hydrated perfluorinated ionomers. An improved active-learning algorithm using a small number of descriptors allows to efficiently construct an accurate and transferable model for this multielemental amorphous polymer. Molecular dynamics simulations accelerated by the machine-learned potentials accurately reproduce the heterogeneous hydrophilic and hydrophobic domains formed in this material as well as proton and water diffusion coefficients under a variety of humidity conditions. Our results reveal pronounced contributions of Grotthuss chains consisting of two to three water molecules to the high proton mobility under strongly humidified conditions.
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Affiliation(s)
- Ryosuke Jinnouchi
- Toyota Central R&D Laboratories., Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192, Japan
| | - Saori Minami
- Toyota Central R&D Laboratories., Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192, Japan
| | - Ferenc Karsai
- VASP Software GmbH, Sensengasse 8, 1090 Vienna, Austria
| | - Carla Verdi
- University of Vienna, Faculty of Physics, Computational Materials Physics, Kolingasse 14-16, 1090 Vienna, Austria
| | - Georg Kresse
- VASP Software GmbH, Sensengasse 8, 1090 Vienna, Austria
- University of Vienna, Faculty of Physics, Computational Materials Physics, Kolingasse 14-16, 1090 Vienna, Austria
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2
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Cui R, Li S, Yu C, Zhou Y. The Evolution of Hydrogen Bond Network in Nafion via Molecular Dynamics Simulation. Macromolecules 2023. [DOI: 10.1021/acs.macromol.2c02106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Affiliation(s)
- Rui Cui
- School of Chemistry & Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Key Laboratory of Electrical Insulation and Thermal Aging, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Shanlong Li
- School of Chemistry & Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Key Laboratory of Electrical Insulation and Thermal Aging, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Chunyang Yu
- School of Chemistry & Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Key Laboratory of Electrical Insulation and Thermal Aging, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Yongfeng Zhou
- School of Chemistry & Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Key Laboratory of Electrical Insulation and Thermal Aging, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
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3
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Crothers AR, Kusoglu A, Radke CJ, Weber AZ. Influence of Mesoscale Interactions on Proton, Water, and Electrokinetic Transport in Solvent-Filled Membranes: Theory and Simulation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:10362-10374. [PMID: 35969508 DOI: 10.1021/acs.langmuir.2c00706] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Transport of protons and water through water-filled, phase-separated cation-exchange membranes occurs through a network of interconnected nanoscale hydrophilic aqueous domains. This paper uses numerical simulations and theory to explore the role of the mesoscale network on water, proton, and electrokinetic transport in perfluorinated sulfonic acid (PFSA) membranes, pertinent to electrochemical energy-conversion devices. Concentrated-solution theory describes microscale transport. Network simulations model mesoscale effects and ascertain macroscopic properties. An experimentally consistent 3D Voronoi-network topology characterizes the interconnected channels in the membrane. Measured water, proton, and electrokinetic transport properties from literature validate calculations of macroscopic properties from network simulations and from effective-medium theory. The results demonstrate that the hydrophilic domain size affects the various microscale, domain-level transport modes dissimilarly, resulting in different distributions of microscale coefficients for each mode of transport. As a result, the network mediates the transport of species nonuniformly with dissimilar calculated tortuosities for water, proton, and electrokinetic transport coefficients (i.e., 4.7, 3.0, and 6.1, respectively, at a water content of 8 H2O molecules per polymer charge equivalent). The dominant water-transport pathways across the membrane are different than those taken by the proton cation. Finally, the distribution of transport properties across the network induces local electrokinetic flows that couple water and proton transport; specifically, local electrokinetic transport induces water chemical-potential gradients that decrease macroscopic conductivity by up to a factor of 3. Macroscopic proton, water, and electrokinetic transport coefficients depend on the collective microscale transport properties of all modes of transport and their distribution across the hydrophilic domain network.
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Affiliation(s)
- Andrew R Crothers
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720 United States
- Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California 94720 United States
| | - Ahmet Kusoglu
- Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California 94720 United States
| | - Clayton J Radke
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720 United States
- Earth and Environmental Sciences Area, Lawrence Berkeley National Laboratory, Berkeley, California 94720 United States
| | - Adam Z Weber
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720 United States
- Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California 94720 United States
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4
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Cui R, Li S, Yu C, Wang Y, Zhou Y. Understanding the mechanism of nitrogen transport in the perfluorinated sulfonic-acid hydrated membranes via molecular dynamics simulations. J Memb Sci 2022. [DOI: 10.1016/j.memsci.2022.120328] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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5
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Zelovich T, Tuckerman ME. Controlling Hydronium Diffusivity in Model Proton Exchange Membranes. J Phys Chem Lett 2022; 13:2245-2253. [PMID: 35238561 DOI: 10.1021/acs.jpclett.1c04071] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Fuel-cell-based proton exchange membranes (PEMs) show great potential as cost-effective and clean energy conversion devices. In our recent work, we found that for the low-hydrated model PEMs with a inhomogeneous water distribution and a sulfonate anionic functional end group (SO3-), the H3O+ reacts with SO3- according to SO3- + H3O+ ↔ SO3H + H2O, indicating that the anions in PEMs become active participants in the hydronium diffusion. In this work, we use fully atomistic ab initio molecular dynamics simulations to elucidate the optimal conditions that would promote the participation of SO3- in the hydronium diffusion mechanism by increasing the H3O+/SO3- reactivity, thus increasing the hydronium diffusivity along the cell. The results presented in this work allow us to suggest a set of design rules for creating novel, highly conductive PEMs operating at high temperatures under a nonuniform water distribution using a linker/anion with a relatively high pKa such as (CH2)2SO3. We expect that the discovery of these key design principles will play an important role in the synthesis of high-performing materials for emerging PEM-based fuel cell technologies.
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Affiliation(s)
- Tamar Zelovich
- Department of Chemistry, New York University, New York, New York 10003, United States
| | - Mark E Tuckerman
- Department of Chemistry, New York University, New York, New York 10003, United States
- Courant Institute of Mathematical Sciences, New York University, New York, New York 10012, United States
- NYU-ECNU Center for Computational Chemistry, New York University Shanghai, 3663 North Zhongshan Rd, Shanghai 200062, China
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6
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Li Z, Chen J, Zhou J, Nie Y, Shen C, Gao S. Trimethyl-Ammonium Alkaline Anion Exchange Membranes with the Vinylbenzyl Chloride/Acrylonitrile Main Chain. Macromol Res 2021. [DOI: 10.1007/s13233-021-9054-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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7
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Zelovich T, Tuckerman ME. OH - and H 3O + Diffusion in Model AEMs and PEMs at Low Hydration: Insights from Ab Initio Molecular Dynamics. MEMBRANES 2021; 11:355. [PMID: 34066142 PMCID: PMC8151131 DOI: 10.3390/membranes11050355] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/25/2021] [Accepted: 05/06/2021] [Indexed: 11/27/2022]
Abstract
Fuel cell-based anion-exchange membranes (AEMs) and proton exchange membranes (PEMs) are considered to have great potential as cost-effective, clean energy conversion devices. However, a fundamental atomistic understanding of the hydroxide and hydronium diffusion mechanisms in the AEM and PEM environment is an ongoing challenge. In this work, we aim to identify the fundamental atomistic steps governing hydroxide and hydronium transport phenomena. The motivation of this work lies in the fact that elucidating the key design differences between the hydroxide and hydronium diffusion mechanisms will play an important role in the discovery and determination of key design principles for the synthesis of new membrane materials with high ion conductivity for use in emerging fuel cell technologies. To this end, ab initio molecular dynamics simulations are presented to explore hydroxide and hydronium ion solvation complexes and diffusion mechanisms in the model AEM and PEM systems at low hydration in confined environments. We find that hydroxide diffusion in AEMs is mostly vehicular, while hydronium diffusion in model PEMs is structural. Furthermore, we find that the region between each pair of cations in AEMs creates a bottleneck for hydroxide diffusion, leading to a suppression of diffusivity, while the anions in PEMs become active participants in the hydronium diffusion, suggesting that the presence of the anions in model PEMs could potentially promote hydronium diffusion.
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Affiliation(s)
- Tamar Zelovich
- Department of Chemistry, New York University (NYU), New York 10003, NY, USA
| | - Mark E. Tuckerman
- Department of Chemistry, New York University (NYU), New York 10003, NY, USA
- Courant Institute of Mathematical Sciences, New York University (NYU), New York, NY 10012, USA
- NYU-ECNU Center for Computational Chemistry at NYU Shanghai, 3663 Zhongshan Rd. North, Shanghai 200062, China
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8
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Crosslinked Proton Exchange Membranes with a Wider Working Temperature Based on Phosphonic Acid Functionalized Siloxane and PPO. Macromol Res 2021. [DOI: 10.1007/s13233-021-9024-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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9
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Dreßler C, Kabbe G, Brehm M, Sebastiani D. Exploring non-equilibrium molecular dynamics of mobile protons in the solid acid CsH2PO4 at the micrometer and microsecond scale. J Chem Phys 2020; 152:164110. [DOI: 10.1063/5.0002167] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Christian Dreßler
- Institute of Chemistry, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - Gabriel Kabbe
- Institute of Chemistry, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - Martin Brehm
- Institute of Chemistry, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - Daniel Sebastiani
- Institute of Chemistry, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
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10
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Freger V. Ion partitioning and permeation in charged low-T* membranes. Adv Colloid Interface Sci 2020; 277:102107. [PMID: 32000110 DOI: 10.1016/j.cis.2020.102107] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 01/15/2020] [Accepted: 01/16/2020] [Indexed: 11/25/2022]
Abstract
Understanding ion transport in membrane materials is key to engineering and development of desalination and water purification technologies as well as electro-membrane applications. To date, modeling of ion transport has mainly relied on mean-field approaches, originally intended for weak inter-ionic interactions, i.e., high reduced temperature T*. This condition is violated in many membranes, which could explain disagreement between predicted trends and experiments. The paper highlights observed discrepancies and develops a new approach based on the concept of ion association, more adequate in the low-T⁎ limit. The new model addresses ion binding and mobility consistently within the same physical picture, applied to different types of single and mixed salts. The resulting relations show a significantly weaker connection between ion partitioning and permeability than the standard ones. Estimates using primitive model (PM) of ions in a homogeneous dielectric suggest that non-PM mechanisms, originating from the molecular structure of the ion-solvating environment, might enhance ion association in membranes. PM analysis also predicts that ion solvation and association must be rigidly related, yet non-PM effects may decouple these phenomena and allow a crossover to non-trivial regimes consistent with experiments and simulations. Despite the crude nature of the presented approach and some questions remaining open, it appears to explain most available experimental data and presents a step towards predictive modeling of ion-selective membrane separations in water-, environment- and energy-related applications.
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11
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Sengupta S, Lyulin AV. Molecular Modeling of Structure and Dynamics of Nafion Protonation States. J Phys Chem B 2019; 123:6882-6891. [PMID: 31306017 PMCID: PMC6691399 DOI: 10.1021/acs.jpcb.9b04534] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 07/08/2019] [Indexed: 11/29/2022]
Abstract
We present the results of the atomistic molecular dynamics modeling of different protonation states of Nafion at varying hydration levels. Previous experiments have shown that the degree of deprotonation (DDP) of the sulfonic acid groups in a Nafion membrane varies significantly upon hydration. Our goal is to provide insights into the effects of variable protonation states and water content on the internal structure and vehicular transport inside the Nafion membrane. The Nafion side chain lengths showed a weak increasing trend with increasing DDP at all hydration levels, exposing more of the sulfonic acid groups to the hydrophilic/water phase. The water-phase characteristic size/diameter decreased with increasing DDP, but, interestingly, the average number of water molecules per cluster increased. The probability of water-hydronium hydrogen bond formation decreased with increasing DDP, despite an increase in the total number of such hydrogen bonds. The water diffusion was largely unaffected by the state of deprotonation. In contrast to that, the hydronium ion diffusion slowed down with increasing DDP in the overall membrane. The hydronium ion residence times around the sulfonic acid group increased with increasing DDP. Our simulations show a strong connection between the morphology of the water domains and protonation states of Nafion. Such a connection can also be expected in polyelectrolyte membranes similar to Nafion.
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Affiliation(s)
- Soumyadipta Sengupta
- Theory
of Polymers and Soft Matter, Department of Applied Physics, and Center for Computational
Energy Research, Department of Applied Physics, Eindhoven University of Technology, Eindhoven 5600 MB, The Netherlands
| | - Alexey V. Lyulin
- Theory
of Polymers and Soft Matter, Department of Applied Physics, and Center for Computational
Energy Research, Department of Applied Physics, Eindhoven University of Technology, Eindhoven 5600 MB, The Netherlands
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12
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Coarse-grained study of the effect of hydrophobic side chain length on cluster size distributions and water diffusion in (amphiphilic-hydrophobic) multi-block co-polymer membranes. POLYMER 2019. [DOI: 10.1016/j.polymer.2019.04.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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13
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Meng Q, Yan H. Theoretical study on the topotactic transformation and memory effect of M (II) M (III)-layered double hydroxides. MOLECULAR SIMULATION 2017. [DOI: 10.1080/08927022.2017.1362107] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Qingting Meng
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing, China
| | - Hong Yan
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing, China
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14
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Modeling and simulation of membrane process. PHYSICAL SCIENCES REVIEWS 2017. [DOI: 10.1515/psr-2017-0023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractThe article presents the different approaches to polymer membrane mathematical modeling. Traditional models based on experimental physicochemical correlations and balance models are presented in the first part. Quantum and molecular mechanics models are presented as they are more popular for polymer membranes in fuel cells. The initial part is enclosed by neural network models which found their use for different types of processes in polymer membranes. The second part is devoted to models of fluid dynamics. The computational fluid dynamics technique can be divided into solving of Navier-Stokes equations and into Boltzmann lattice models. Both approaches are presented focusing on membrane processes.
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15
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Molecular dynamics study of confined structure and diffusion of hydrated proton in Hyfion® perfluorosulfonic acid membranes. Chem Eng Sci 2017. [DOI: 10.1016/j.ces.2016.10.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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16
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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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17
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Feng C, He PF. Moisture and thermal expansion properties and mechanism of interaction between ions of a Nafion-based membrane electrode assembly. RSC Adv 2017. [DOI: 10.1039/c7ra04191h] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The coefficient of moisture and thermal expansion for each layer of membrane electrode assembly.
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Affiliation(s)
- C. Feng
- School of Materials Science and Engineering
- Shanghai Key Lab of Metal Functional Materials
- Tongji University
- Shanghai 201804
- China
| | - P. F. He
- School of Aerospace Engineering and Applied Mechanics
- Tongji University
- Shanghai 200092
- China
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18
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Lu J, Jacobson LC, Perez Sirkin YA, Molinero V. High-Resolution Coarse-Grained Model of Hydrated Anion-Exchange Membranes that Accounts for Hydrophobic and Ionic Interactions through Short-Ranged Potentials. J Chem Theory Comput 2016; 13:245-264. [PMID: 28068769 DOI: 10.1021/acs.jctc.6b00874] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Jibao Lu
- Department
of Chemistry, The University of Utah, Salt Lake City, Utah 84112-0850, United States
| | - Liam C. Jacobson
- Department
of Chemistry, The University of Utah, Salt Lake City, Utah 84112-0850, United States
| | - Yamila A. Perez Sirkin
- Departamento
de Química Inorgánica, Analítica y Química
Física, and INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EHA, Argentina
| | - Valeria Molinero
- Department
of Chemistry, The University of Utah, Salt Lake City, Utah 84112-0850, United States
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19
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Zhang ST, Dou Y, Zhou J, Pu M, Yan H, Wei M, Evans DG, Duan X. DFT-Based Simulation and Experimental Validation of the Topotactic Transformation of MgAl Layered Double Hydroxides. Chemphyschem 2016; 17:2754-66. [DOI: 10.1002/cphc.201600354] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Indexed: 01/08/2023]
Affiliation(s)
- Shi-Tong Zhang
- State Key Laboratory of Chemical Resource Engineering; Beijing University of Chemical Technology; Beijing 100029 P.R. China
| | - Yibo Dou
- State Key Laboratory of Chemical Resource Engineering; Beijing University of Chemical Technology; Beijing 100029 P.R. China
| | - Junyao Zhou
- State Key Laboratory of Chemical Resource Engineering; Beijing University of Chemical Technology; Beijing 100029 P.R. China
| | - Min Pu
- State Key Laboratory of Chemical Resource Engineering; Beijing University of Chemical Technology; Beijing 100029 P.R. China
| | - Hong Yan
- State Key Laboratory of Chemical Resource Engineering; Beijing University of Chemical Technology; Beijing 100029 P.R. China
| | - Min Wei
- State Key Laboratory of Chemical Resource Engineering; Beijing University of Chemical Technology; Beijing 100029 P.R. China
| | - David G. Evans
- State Key Laboratory of Chemical Resource Engineering; Beijing University of Chemical Technology; Beijing 100029 P.R. China
| | - Xue Duan
- State Key Laboratory of Chemical Resource Engineering; Beijing University of Chemical Technology; Beijing 100029 P.R. China
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20
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Dorenbos G. Water Diffusion Dependence on Amphiphilic Block Design in (Amphiphilic-Hydrophobic) Diblock Copolymer Membranes. J Phys Chem B 2016; 120:5634-45. [PMID: 27266679 DOI: 10.1021/acs.jpcb.6b03171] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Polyelectrolyte membranes (PEMs) are applied in polyelectrolyte fuel cells (PEFC). The proton conductive pathways within PEMs are provided by nanometer-sized water containing pores. Large-scale application of PEFC requires the production of low-cost membranes with high proton conductivity and therefore good connected pore networks. Pore network formation within four alternative model diblock (hydrophobic_amphiphilic) copolymers in the presence of water is studied by dissipative particle dynamics. Each hydrophobic block contains 50 consecutively connected hydrophobic (A) fragments, and amphiphilic blocks contain 40 hydrophobic A beads and 10 hydrophilic C beads. For one amphiphilic block the C beads are distributed uniformly along the backbone. For the other architectures C beads are located at the end of the side chains attached at regular intervals along the backbone. Water diffusion through the pores is modeled by Monte Carlo tracer diffusion through mapped morphologies. Diffusion is highest for the grafted architectures and increases with increase of length of the side chains. A consistent picture emerges in which diffusion strongly increases with the value of ⟨Nbond⟩ within the amphiphilic block, where ⟨Nbond⟩ is the average number of bonds between hydrophobic A beads and the nearest C bead.
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Affiliation(s)
- Gert Dorenbos
- T410-1118, sano 1107-2, Belle Crea 502, Susono, Japan
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21
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Dorenbos G. Modelling linear and branched amphiphilic star polymer electrolyte membranes and verification of the bond counting method. RSC Adv 2016. [DOI: 10.1039/c5ra24172c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Water diffusion through hydrated amphiphilic star polymer membranes depends strongly on hydrophilic position within the linear and Y-shaped arms.
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22
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Dorenbos G. Morphology and diffusion within model membranes: Application of bond counting method to architectures with bimodal side chain length distributions. Eur Polym J 2015. [DOI: 10.1016/j.eurpolymj.2015.05.028] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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23
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Dorenbos G. Searching for low percolation thresholds within amphiphilic polymer membranes: The effect of side chain branching. J Chem Phys 2015; 142:224902. [DOI: 10.1063/1.4922156] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
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24
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25
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Dorenbos G. Water diffusion within hydrated model grafted polymeric membranes with bimodal side chain length distributions. SOFT MATTER 2015; 11:2794-2805. [PMID: 25703230 DOI: 10.1039/c5sm00016e] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The effect of bimodal side chain length distributions on pore morphology and solvent diffusion within hydrated amphiphilic polymeric membranes is predicted. Seven polymeric architectures are constructed from hydrophobic backbones from which at regular intervals side chains branch off that are alternatingly short (composed of p hydrophobic A fragments or beads) and long (q A fragments, q > p). The side chains are end-linked with a hydrophilic C fragment. Pore morphologies at a water volume fraction of 0.16 are calculated by dissipative particle dynamics (DPD). Water diffusion through the water containing pores is calculated by tracer diffusion calculations through 140 selected snapshots and from the water bead motions. Diffusion constants decrease with difference in side chain lengths, q - p. Overall, the distance between pores also decreases with q - p. The results are explained by counting for every architecture the average number of bonds 〈N(bond)〉 between an A and the nearest C fragment. These results are in line with a database that contains more than 60 architectures. Diffusion constants tend to increase linearly with 〈N(bond)〉|C|(-1)|A|, where |C| and |A| are the C and A bead fractions within the architecture. 〈N(bond)〉 is therefore expected to be an interesting design parameter for obtaining low percolation thresholds for solvent and/or proton diffusion.
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Affiliation(s)
- G Dorenbos
- 410-1118, 1107-2 sano, Belle Crea 502, Susono-shi, Shizuoka-ken, Japan.
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26
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Daly KB, Panagiotopoulos AZ, Debenedetti PG, Benziger JB. Viscosity of Nafion Oligomers as a Function of Hydration and Counterion Type: A Molecular Dynamics Study. J Phys Chem B 2014; 118:13981-91. [DOI: 10.1021/jp509061z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kevin B. Daly
- Department
of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | | | - Pablo G. Debenedetti
- Department
of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Jay B. Benziger
- Department
of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
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Dorenbos G. Pore design within amphiphilic polymer membranes: linear versus Y-shaped side chain architectures. RSC Adv 2014. [DOI: 10.1039/c4ra00919c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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Zhang XY, Ding YH. Thickness-dependent structural and transport behaviors in the platinum–Nafion interface: a molecular dynamics investigation. RSC Adv 2014. [DOI: 10.1039/c4ra05523c] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Savage J, Voth GA. Persistent Subdiffusive Proton Transport in Perfluorosulfonic Acid Membranes. J Phys Chem Lett 2014; 5:3037-3042. [PMID: 26278256 DOI: 10.1021/jz5014467] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Proton transport (PT) in solutions of small amphiphiles in water has previously been shown to be subdiffusive for long times. The present study analyzes simulations of hydrated perfluorosulfonic acid (PFSA) membranes in order to determine whether PT is also subdiffusive in these important amphiphilic systems. We show that PT is indeed subdiffusive for several hundred picoseconds for all hydration levels examined, and the subdiffusive behavior is highly dependent on water concentration. We also investigate the caging of the excess proton using a recently developed technique and show that the excess proton exhibits caging effects up to at least 1 ns in PFSA systems. In order to fully characterize the long-time behavior of PT in PFSAs, these results demonstrate that multiple nanosecond trajectories are needed, well beyond the current capabilities of ab initio molecular dynamics.
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Affiliation(s)
- John Savage
- Department of Chemistry, James Franck Institute, and Computation Institute, University of Chicago, Chicago, Illinois 60637, United States
| | - Gregory A Voth
- Department of Chemistry, James Franck Institute, and Computation Institute, University of Chicago, Chicago, Illinois 60637, United States
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