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Rahbari A, Hartkamp R, Moultos OA, Bos A, van den Broeke LJP, Ramdin M, Dubbeldam D, Lyulin AV, Vlugt TJH. Electro-osmotic Drag and Thermodynamic Properties of Water in Hydrated Nafion Membranes from Molecular Dynamics. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:8121-8133. [PMID: 35592735 PMCID: PMC9109139 DOI: 10.1021/acs.jpcc.2c01226] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 04/18/2022] [Indexed: 06/15/2023]
Abstract
One of the important parameters in water management of proton exchange membranes is the electro-osmotic drag (EOD) coefficient of water. The value of the EOD coefficient is difficult to justify, and available literature data on this for Nafion membranes show scattering from in experiments and simulations. Here, we use a classical all-atom model to compute the EOD coefficient and thermodynamic properties of water from molecular dynamics simulations for temperatures between 330 and 420 K, and for different water contents between λ = 5 and λ = 20. λ is the ratio between the moles of water molecules to the moles of sulfonic acid sites. This classical model does not capture the Grotthuss mechanism; however, it is shown that it can predict the EOD coefficient within the range of experimental values for λ = 5 where the vehicular mechanism dominates proton transfer. For λ > 5, the Grotthuss mechanism becomes dominant. To obtain the EOD coefficient, average velocities of water and ions are computed by imposing different electric fields to the system. Our results show that the velocities of water and hydronium scale linearly with the electric field, resulting in a constant ratio of ca. 0.4 within the error bars. We find that the EOD coefficient of water linearly increases from 2 at λ = 5 to 8 at λ = 20 and the results are not sensitive to temperature. The EOD coefficient at λ = 5 is within the range of experimental values, confirming that the model can capture the vehicular transport of protons well. At λ = 20, due to the absence of proton hopping in the model, the EOD coefficient is overestimated by a factor of 3 compared to experimental values. To analyze the interactions between water and Nafion, the partial molar enthalpies and partial molar volumes of water are computed from molecular dynamics simulations. At different water uptakes, multiple linear regression is used on raw simulation data within a narrow composition range of water inside the Nafion membrane. The partial molar volumes and partial molar excess enthalpies of water asymptotically approach the molar volumes and molar excess enthalpies of pure water for water uptakes above 5. This confirms the model can capture the bulklike behavior of water in the Nafion at high water uptakes.
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Affiliation(s)
- Ahmadreza Rahbari
- Engineering
Thermodynamics, Process & Energy Department, Faculty of Mechanical,
Maritime and Materials Engineering, Delft
University of Technology, Leeghwaterstraat 39, 2628CB Delft, The Netherlands
- XINTC
global, Wesselseweg 134, 3774 RL Kootwijkerbroek, The
Netherlands
| | - Remco Hartkamp
- Engineering
Thermodynamics, Process & Energy Department, Faculty of Mechanical,
Maritime and Materials Engineering, Delft
University of Technology, Leeghwaterstraat 39, 2628CB Delft, The Netherlands
| | - Othonas A. Moultos
- Engineering
Thermodynamics, Process & Energy Department, Faculty of Mechanical,
Maritime and Materials Engineering, Delft
University of Technology, Leeghwaterstraat 39, 2628CB Delft, The Netherlands
| | - Albert Bos
- XINTC
global, Wesselseweg 134, 3774 RL Kootwijkerbroek, The
Netherlands
| | - Leo J. P. van den Broeke
- Engineering
Thermodynamics, Process & Energy Department, Faculty of Mechanical,
Maritime and Materials Engineering, Delft
University of Technology, Leeghwaterstraat 39, 2628CB Delft, The Netherlands
| | - Mahinder Ramdin
- Engineering
Thermodynamics, Process & Energy Department, Faculty of Mechanical,
Maritime and Materials Engineering, Delft
University of Technology, Leeghwaterstraat 39, 2628CB Delft, The Netherlands
| | - David Dubbeldam
- Van’t
Hoff Institute for Molecular Sciences, University
of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands
| | - Alexey V. Lyulin
- Soft
Matter and Biological Physics, Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
- Center
for Computational Energy Research, P.O.
Box 6336, 5600 HH Eindhoven, The Netherlands
| | - Thijs J. H. Vlugt
- Engineering
Thermodynamics, Process & Energy Department, Faculty of Mechanical,
Maritime and Materials Engineering, Delft
University of Technology, Leeghwaterstraat 39, 2628CB Delft, The Netherlands
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2
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Urata S, Kuo AT, Murofushi H. Self-assembly of the cationic surfactant n-hexadecyl-trimethylammonium chloride in methyltrimethoxysilane aqueous solution: classical and reactive molecular dynamics simulations. Phys Chem Chem Phys 2021; 23:14486-14495. [PMID: 34184007 DOI: 10.1039/d1cp01462e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A flexible aerogel polymerized from methyltrimethoxysilane (MTMS) shows great promise as a high-performance insulator owing to its substantially low thermal conductivity and mechanical flexibility, attributed to its porous microstructure and organic-inorganic hybridization, respectively, which promote its industrial applications. Conventionally, the cationic surfactant n-hexadecyltrimethylammonium chloride (CTAC) is utilized to experimentally control the nanoscale microstructure and, consequently, the flexibility of the MTMS aerogel; however, the mechanism through which CTAC prevents MTMS aggregation in the solution is not yet fully understood. This study unravels the role of CTAC in preventing MTMS aggregation in aqueous solution using both classical and reactive molecular dynamics simulations. We found that CTAC molecules can form self-aggregates even when the polymerization of MTMS progresses and then the MTMS-derived oligomer turns to be hydrophobic in aqueous solution. In summary, the self-assemblies of CTAC disperse among the MTMS associations and effectively prevent MTMS clustering, and this is considered as the key mechanism underlying the formation of a flexible microstructure of the hybrid aerogel.
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Affiliation(s)
- Shingo Urata
- Innovative Technology Laboratories, AGC Inc., 1-1 Suehiro-cho, Tsurumi-ku, Yokohama, Japan.
| | - An-Tsung Kuo
- Materials Integration Laboratories, AGC Inc., Japan
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3
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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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4
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Nimmanpipug P, Kodchakorn K, Lee VS, Yana J, Jarumaneeroj C, Phongtamrug S, Chirachanchai S. Structural and transport phenomena of urocanate-based proton carrier in sulfonated poly(ether ether ketone) membrane composite. ACTA ACUST UNITED AC 2018. [DOI: 10.1002/polb.24753] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Piyarat Nimmanpipug
- Computational Simulation and Molecular Modeling Laboratory (CSML), Department of Chemistry, Faculty of Science and Graduate School; Chiang Mai University; Chiang Mai 50200 Thailand
| | - Kanchanok Kodchakorn
- Computational Simulation and Molecular Modeling Laboratory (CSML), Department of Chemistry, Faculty of Science and Graduate School; Chiang Mai University; Chiang Mai 50200 Thailand
- Doctor of Philosophy Program in Chemistry, Faculty of Science; Chiang Mai University; Chiang Mai 50200 Thailand
| | | | - Janchai Yana
- Department of Chemistry, Faculty of Science and Technology; Chiang Mai Rajabhat University; Chiang Mai 50300 Thailand
| | - Chatchai Jarumaneeroj
- The Petroleum and Petrochemical College; Chulalongkorn University; Soi Chula 12, Phyathai Rd., Pathumwan, Bangkok 10330 Thailand
| | - Suttinun Phongtamrug
- Department of Industrial Chemistry, Faculty of Applied Science; King Mongkut's University of Technology North Bangkok; Bangkok 10800 Thailand
| | - Suwabun Chirachanchai
- The Petroleum and Petrochemical College; Chulalongkorn University; Soi Chula 12, Phyathai Rd., Pathumwan, Bangkok 10330 Thailand
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5
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Shaari N, Kamarudin SK, Basri S. Molecular dynamics simulations of sodium alginate/sulfonated graphene oxide membranes properties. Heliyon 2018; 4:e00808. [PMID: 30246163 PMCID: PMC6146620 DOI: 10.1016/j.heliyon.2018.e00808] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 08/04/2018] [Accepted: 09/13/2018] [Indexed: 11/15/2022] Open
Abstract
The influence of methanol as a solvent on the properties of sodium alginate/sulfonated graphene oxide (SA/SGO) membranes was explored in water-methanol mixed conditions with various methanol concentrations and temperatures through molecular dynamics simulations. The methanol uptake of the membrane showed an isolation phase determined from the simulation results. The distance between the sulfonic acid groups increased in higher methanol concentrations, as observed from S-S RDFs. Furthermore, the distance between the SA-chain RDFs and the solvent molecules was analysed to determine a) the affinity of water towards the sulfonic acid groups and b) the affinity of the aromatic backbone of the SA towards methanol molecules. A decrease in water molecule diffusion led to an increase in methanol diffusion and uptake. SA/SGO membranes exhibited a smaller diffusion coefficient than that for the Nafion membranes, as calculated from simulation results and compared to the experimental work. Additionally, the diffusion ability increased at higher temperatures for all permeants. The interaction information obtained is useful for DMFC applications.
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Affiliation(s)
- N Shaari
- Fuel Cell Institute, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
| | - S K Kamarudin
- Fuel Cell Institute, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia.,Chemical Engineering Programme, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
| | - S Basri
- Fuel Cell Institute, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
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Bahlakeh G, Mahdi Hasani-Sadrabadi M, Jacob KI. Morphological and transport characteristics of swollen chitosan-based proton exchange membranes studied by molecular modeling. Biopolymers 2016; 107:5-19. [DOI: 10.1002/bip.22979] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2016] [Revised: 07/21/2016] [Accepted: 08/17/2016] [Indexed: 02/03/2023]
Affiliation(s)
- Ghasem Bahlakeh
- Department of Engineering and Technology; Golestan University; Aliabad Katool Iran
| | - Mohammad Mahdi Hasani-Sadrabadi
- Parker H, Petit Institute for Bioengineering and Bioscience, G.W. Woodruff School of Mechanical, Engineering; Georgia Institute of Technology; Atlanta 30332 GA
- Laboratoire de Microsystemes (LMIS4), Institute of Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL); Lausanne Switzerland
| | - Karl I. Jacob
- Parker H, Petit Institute for Bioengineering and Bioscience, G.W. Woodruff School of Mechanical, Engineering; Georgia Institute of Technology; Atlanta 30332 GA
- School of Materials Science and Engineering; Georgia Institute of Technology; Atlanta GA 30332
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7
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Mahajan CV, Ganesan V. Influence of Hydrogen Bonding Effects on Methanol and Water Diffusivities in Acid–Base Polymer Blend Membranes of Sulfonated Poly(ether ether ketone) and Base Tethered Polysulfone. J Phys Chem B 2013; 117:5315-29. [DOI: 10.1021/jp3121512] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Chetan V. Mahajan
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
| | - Venkat Ganesan
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
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8
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Structure and proton transport in proton exchange membranes based on cross-linked sulfonated poly (1, 3-cyclohexadiene) with varying local acid environment. POLYMER 2013. [DOI: 10.1016/j.polymer.2013.03.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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9
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Wang C, Paddison SJ. Hydration and proton transfer in highly sulfonated poly(phenylene sulfone) ionomers: an ab initio study. J Phys Chem A 2013; 117:650-60. [PMID: 23286778 DOI: 10.1021/jp310354p] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The need to operate proton exchange membrane fuel cells under hot and dry conditions has driven the synthesis and testing of sulfonated poly(phenylene) sulfone (sPSO(2)) ionomers. The primary hydration and energetics associated with the transfer of protons in oligomeric fragments of two sPSO(2)ionomers were evaluated through first-principles electronic structures calculations. Our results indicate that the interaction between neighboring sulfonic acid groups affect both theconformation and stability of the fragments. The number of water molecules required to affect the transfer of a proton in the first hydration shell was observed to be a function of the hydrogen bonding in proximity of the sulfonic acid groups: three H(2)O for the meta- and four H(2)O for the ortho-conformations. Calculations of the rotational energy surfaces indicate that the aromatic backbones of sPSO(2) are much stiffer than the polytetrafluoroethylene (PTFE) backbones in perfluorosulfonic acid (PFSA) ionomers: the largest energy penalty for rotating phenylene rings (i.e., 15.5 kcal/mol for ortho-ortho-sPSO(2)) is nearly twice that computed for the rotation of a CF(2) unit in a PTFE backbone. The energetics for the transfer of various protons in proximity to one or two sulfonate groups (-SO(3)(-)) was also determined. The computed energy barrier for proton transfer when only one sulfonic acid group is present is approximately 1.9 kcal/mol, which is 2.1 kcal/mol lower than similar calculations for PFSA systems. When two sulfonic acid groups are bridged by water molecules, a symmetric bidirectional transfer occurs, which gives a substantially small energy barrier of only 0.7 kcal/mol.
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Affiliation(s)
- Chen Wang
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
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10
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Wang Q, Suraweera NS, Keffer DJ, Deng S, Mays J. Atomistic and Coarse-Grained Molecular Dynamics Simulation of a Cross-Linked Sulfonated Poly(1,3-cyclohexadiene)-Based Proton Exchange Membrane. Macromolecules 2012. [DOI: 10.1021/ma300383z] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Qifei Wang
- Department of Chemical and Biomolecular
Engineering, University of Tennessee, Knoxville,
Tennessee 37996, United States
| | - Nethika S. Suraweera
- Department of Chemical and Biomolecular
Engineering, University of Tennessee, Knoxville,
Tennessee 37996, United States
| | - David J. Keffer
- Department of Chemical and Biomolecular
Engineering, University of Tennessee, Knoxville,
Tennessee 37996, United States
| | - Suxiang Deng
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Jimmy Mays
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
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11
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Mahajan CV, Ganesan V. Correction to “Atomistic Simulations of Structure of Solvated Sulfonated Poly(ether ether ketone) Membranes and Their Comparisons to Nafion: II. Structure and Transport Properties of Water, Hydronium Ions, and Methanol”. J Phys Chem B 2012. [DOI: 10.1021/jp303447m] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Chetan V. Mahajan
- Department of Chemical
Engineering, University of Texas at Austin, Austin,
Texas 78712, United States
| | - Venkat Ganesan
- Department of Chemical
Engineering, University of Texas at Austin, Austin,
Texas 78712, United States
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12
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Clark II JK, Paddison SJ, Hamrock SJ. The effect of hydrogen bond reorganization and equivalent weight on proton transfer in 3M perfluorosulfonic acid ionomers. Phys Chem Chem Phys 2012; 14:16349-59. [DOI: 10.1039/c2cp42678a] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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13
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Abroshan H, Akbarzadeh H, Taherkhani F, Parsafar G. Effect of water–methanol content on the structure of Nafion in the sandwich model and solvent dynamics in nano-channels; a molecular dynamics study. Mol Phys 2011. [DOI: 10.1080/00268976.2010.549846] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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14
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Abroshan H, Akbarzadeh H, Taherkhani F, Parsafar G. Effect of a monomeric sequence on the structure of hydrated Nafion in the sandwich model and solvent dynamics in nano-channels: a molecular dynamic study. Mol Phys 2010. [DOI: 10.1080/00268976.2010.511635] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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15
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Wu L, Huang C, Woo JJ, Wu D, Yun SH, Seo SJ, Xu T, Moon SH. Modifying a Proton Conductive Membrane by Embedding a “Barrier”. J Phys Chem B 2010; 114:13121-7. [DOI: 10.1021/jp104514t] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Liang Wu
- CAS Key Laboratory of Soft Matter Chemistry, Laboratory of Functional Membranes, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China, and Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 500-712, Republic of Korea
| | - Chuanhui Huang
- CAS Key Laboratory of Soft Matter Chemistry, Laboratory of Functional Membranes, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China, and Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 500-712, Republic of Korea
| | - Jung-Je Woo
- CAS Key Laboratory of Soft Matter Chemistry, Laboratory of Functional Membranes, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China, and Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 500-712, Republic of Korea
| | - Dan Wu
- CAS Key Laboratory of Soft Matter Chemistry, Laboratory of Functional Membranes, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China, and Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 500-712, Republic of Korea
| | - Sung-Hyun Yun
- CAS Key Laboratory of Soft Matter Chemistry, Laboratory of Functional Membranes, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China, and Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 500-712, Republic of Korea
| | - Seok-Jun Seo
- CAS Key Laboratory of Soft Matter Chemistry, Laboratory of Functional Membranes, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China, and Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 500-712, Republic of Korea
| | - Tongwen Xu
- CAS Key Laboratory of Soft Matter Chemistry, Laboratory of Functional Membranes, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China, and Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 500-712, Republic of Korea
| | - Seung-Hyeon Moon
- CAS Key Laboratory of Soft Matter Chemistry, Laboratory of Functional Membranes, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China, and Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 500-712, Republic of Korea
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16
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Mahajan CV, Ganesan V. Atomistic Simulations of Structure of Solvated Sulfonated Poly(ether ether ketone) Membranes and Their Comparisons to Nafion: II. Structure and Transport Properties of Water, Hydronium Ions, and Methanol. J Phys Chem B 2010; 114:8367-73. [DOI: 10.1021/jp1040794] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Chetan V. Mahajan
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712
| | - Venkat Ganesan
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712
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17
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Mahajan CV, Ganesan V. Atomistic Simulations of Structure of Solvated Sulfonated Poly(ether ether ketone) Membranes and Their Comparisons to Nafion: I. Nanophase Segregation and Hydrophilic Domains. J Phys Chem B 2010; 114:8357-66. [DOI: 10.1021/jp104078h] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Chetan V. Mahajan
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712
| | - Venkat Ganesan
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712
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18
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Habenicht BF, Paddison SJ, Tuckerman ME. The effects of the hydrophobic environment on proton mobility in perfluorosulfonic acid systems: an ab initio molecular dynamics study. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/c0jm00253d] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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19
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FANG Y, MIAO R, WANG T, WANG X, FANG S. RESEARCH PROGRESS OF POLYMER PROTON EXCHANGE MEMBRANES FOR DIRECT METHANOL FUEL CELLS. ACTA POLYM SIN 2009. [DOI: 10.3724/sp.j.1105.2009.00992] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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20
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Wu D, Paddison SJ, Elliott JA. Effect of Molecular Weight on Hydrated Morphologies of the Short-Side-Chain Perfluorosulfonic Acid Membrane. Macromolecules 2009. [DOI: 10.1021/ma900016w] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dongsheng Wu
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, and Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge, CB2 3QZ, U.K
| | - Stephen J. Paddison
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, and Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge, CB2 3QZ, U.K
| | - James A. Elliott
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, and Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge, CB2 3QZ, U.K
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21
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Zhang QG, Liu QL, Chen Y, Wu JY, Zhu AM. Microstructure dependent diffusion of water–ethanol in swollen poly(vinyl alcohol): A molecular dynamics simulation study. Chem Eng Sci 2009. [DOI: 10.1016/j.ces.2008.10.028] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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22
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Choe YK, Tsuchida E, Ikeshoji T, Yamakawa S, Hyodo SA. Nature of proton dynamics in a polymer electrolyte membrane, nafion: a first-principles molecular dynamics study. Phys Chem Chem Phys 2009; 11:3892-9. [PMID: 19440617 DOI: 10.1039/b819535h] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Yoong-Kee Choe
- National Institute of Advanced Industrial Science and Technology , Tsukuba, 305-8578, Japan.
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23
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Cui S, Liu J, Selvan ME, Paddison SJ, Keffer DJ, Edwards BJ. Comparison of the hydration and diffusion of protons in perfluorosulfonic acid membranes with molecular dynamics simulations. scui@utk.edu. J Phys Chem B 2008; 112:13273-84. [PMID: 18826266 DOI: 10.1021/jp8039803] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Classical molecular dynamics (MD) simulations were performed to determine the hydrated morphology and hydronium ion diffusion coefficients in two different perfluorosulfonic acid (PFSA) membranes as functions of water content. The structural and transport properties of 1143 equivalent weight (EW) Nafion, with its relatively long perfluoroether side chains, are compared to the short-side-chain (SSC) PFSA ionomer at an EW of 977. The separation of the side chains was kept uniform in both ionomers consisting of -(CF 2) 15- units in the backbone, and the degree of hydration was varied from 5 to 20 weight % water. The MD simulations indicated that the distribution of water clusters is more dispersed in the SSC ionomer, which leads to a more connected water-channel network at the low water contents. This suggests that the SSC ionomer may be more inclined to form sample-spanning aqueous domains through which transport of water and protons may occur. The diffusion coefficients for both hydronium ions and water molecules were calculated at hydration levels of 4.4, 6.4, 9.6, and 12.8 H 2O/SO 3H for each ionomer. When compared to experimental proton diffusion coefficients, this suggests that as the water content is increased the contribution of proton hopping to the overall proton diffusion increases.
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Affiliation(s)
- Shengting Cui
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee, 37996-2200, USA.
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Akinaga Y, Hyodo SA, Ikeshoji T. Lattice Boltzmann simulations for proton transport in 2-D model channels of Nafion. Phys Chem Chem Phys 2008; 10:5678-88. [PMID: 18956102 DOI: 10.1039/b805107k] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Proton conductance in a 2-D channel with a slab-like structure was studied to verify that the lattice Boltzmann method (LBM) can be used as a simulation tool for proton conduction in a Nafion membrane, which is a mesoscopic system with a highly disordered porous structure. Diffusion resulting from a concentration gradient and migration by an electrostatic force were considered as the origins of proton transport. The electrostatic force acting on a proton was computed by solving the Poisson equation. The proton concentration in the membrane is expressed as a continuous function and the sulfonic charge is placed discretely. The space-averaged conductance of protons in a nonequilibrium stationary state was evaluated as a function of the structural parameters: namely, channel width and distribution of the sulfonic groups. The resulting space-averaged conductance deviates from the bulk values, depending particularly on the sulfonic group distribution. Details of the simulation scheme are described and the applicability of the present scheme to real membranes is discussed.
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Affiliation(s)
- Yoshinobu Akinaga
- Research Institute for Computational Sciences (RICS), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan.
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Vishnyakov A, Neimark AV. Specifics of solvation of sulfonated polyelectrolytes in water, dimethylmethylphosphonate, and their mixture: A molecular simulation study. J Chem Phys 2008; 128:164902. [PMID: 18447495 DOI: 10.1063/1.2899327] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Affiliation(s)
- Aleksey Vishnyakov
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, 98 Brett Road, Piscataway, New Jersey 08854, USA
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26
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Hristov IH, Paddison SJ, Paul R. Molecular Modeling of Proton Transport in the Short-Side-Chain Perfluorosulfonic Acid Ionomer. J Phys Chem B 2008; 112:2937-49. [DOI: 10.1021/jp7108434] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Iordan H. Hristov
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, T2N 1N4 Canada, and Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996
| | - Stephen J. Paddison
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, T2N 1N4 Canada, and Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996
| | - Reginald Paul
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, T2N 1N4 Canada, and Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996
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27
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Brandell D, Karo J, Liivat A, Thomas JO. Molecular dynamics studies of the Nafion®, Dow® and Aciplex® fuel-cell polymer membrane systems. J Mol Model 2007; 13:1039-46. [PMID: 17665227 DOI: 10.1007/s00894-007-0230-7] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Accepted: 06/26/2007] [Indexed: 10/23/2022]
Abstract
The Nafion, Dow and Aciplex systems--where the prime differences lies in the side-chain length--have been studied by molecular dynamics (MD) simulation under standard pressure and temperature conditions for two different levels of hydration: 5 and 15 water molecules per (H)SO(3) end-group. Structural features such as water clustering, water-channel dimensions and topology, and the dynamics of the hydronium ions and water molecules have all been analysed in relation to the dynamical properties of the polymer backbone and side-chains. It is generally found that mobility is promoted by a high water content, with the side-chains participating actively in the H(3)O(+)/H(2)O transport mechanism. Nafion, whose side-chain length is intermediate of the three polymers studied, is found to have the most mobile polymer side-chains at the higher level of hydration, suggesting that there could be an optimal side-chain length in these systems. There are also some indications that the water-channel network connectivity is optimal for high water-content Nafion system, and that this could explain why Nafion appears to exhibit the most favourable overall hydronium/water mobility.
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Affiliation(s)
- Daniel Brandell
- Chemistry Department, Macromolecular and Interfaces Institute, Virginia Tech, Blacksburg, VA 24061, USA.
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28
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Elliott JA, Paddison SJ. Modelling of morphology and proton transport in PFSA membranes. Phys Chem Chem Phys 2007; 9:2602-18. [PMID: 17627306 DOI: 10.1039/b701234a] [Citation(s) in RCA: 194] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Computational modelling studies of the structure of perfluorosulfonic acid (PFSA) ionomer membranes consistently exhibit a nanoscopic phase-separated morphology in which the ionic side chains and aqueous counterions segregate from the fluorocarbon backbone to form clusters or channels. Although these investigations do not unambiguously predict the size or shape of the clusters, and whether or not the channels percolate the matrix or if the connections between them are more transient, the sequence of co-monomers along the main chain appears strongly to influence the domain size of the ionic regions, with more blocky sequences giving rise to larger domain sizes. The fundamental insight that substantial rearrangement of the sulfonic acid terminated side chains and fluorocarbon backbone takes place during swelling or shrinkage is borne out by both molecular and mesoscale simulations of model PFSA polymers, along with ab initio electronic structure calculations of minimally hydrated oligomeric fragments. Molecular-level modelling of proton transport in PFSA membranes attests to the complexity of the underlying mechanisms and the need to examine the chemical and physical processes at several distinct time and length scales. These investigations have revealed that the conformation of the fluorocarbon backbone, flexibility of the sidechains, and degree of aggregation and association of the sulfonic acid groups under minimally hydrated conditions collectively control the dissociation of the protons and the formation of Zundel and Eigen cations. The former appear to be the dominant charge carriers when the limiting water content allows only for the formation of a contact ion pair with the tethered sulfonate anion. As the water content increases, solvent-separated Eigen ions begin to appear, indicating that the dominant mechanism for diffusion of protons occurs over a region approximately 4 A away from the sulfonate groups. Finally, both the vehicular and Grotthuss shuttling mechanisms contribute to the mobility of the protons but, surprisingly, they are not always correlated, resulting in a lower overall diffusion coefficient. In summary, as the preceding observations indicate, the state of computational modelling of PFSA membranes has progressed sufficiently over the last decade to enable its use as a powerful predictive tool with which to guide the process of designing novel membrane materials for fuel cell applications.
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Affiliation(s)
- James A Elliott
- Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge, CB2 3QZ, UK.
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29
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Saito M, Tsuzuki S, Hayamizu K, Okada T. Alcohol and Proton Transport in Perfluorinated Ionomer Membranes for Fuel Cells. J Phys Chem B 2006; 110:24410-7. [PMID: 17134195 DOI: 10.1021/jp0643496] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
To clarify the transport mechanisms of alcohols and proton in perfluorosulfonated ionomer (PFSI) membranes for fuel cells, four membranes having different equivalent weight (EW) values were examined. Membranes were immersed in methanol, ethanol, and 2-propanol to prepare a total of 12 samples, and membrane swelling, mass (alcohol and proton) transports, and interactions between alcohols and proton were investigated systematically in the fully penetrated state. The membrane expansion fraction theta and alcohol content lambda increased with decreasing the EW value for all the samples. The self-diffusion coefficients (D's) of the alkyl group and of OH (including protons) were measured separately by the pulsed-gradient spin-echo (PGSE)-NMR method and the D's also increased with decreasing the EW value. These results implied that the alcohols penetrate into the hydrophilic regions of the PFSI membranes and diffuse through the space expanded by the alcohols. The ionic cluster regions formed by the alcohols resemble those induced by water in the water swollen membrane, where protons dissociated from sulfonic acid groups transport through the regions together with water molecules. The D values decreased with increasing the molecular weight of alcohols. This trend was supported by activation energies Ea estimated from the Arrhenius plots of D in the temperature range from 30 to -40 degrees C. The PGSE-NMR measurements also revealed that protons move faster than the alkyl groups in the membranes. The proton transport by the Grotthuss (hopping) mechanism was facilitated by the increase of the alcohol content and the decrease of the molecular weight. This result was also supported by the experimental results of proton conductivity kappa and mobility u(H(+)). Density functional theory (DFT) calculations of the interaction energy DeltaE(int) between proton and alcohol (including OH) showed that the /DeltaE(int)/ increases with increasing the molecular weight of alcohols, which is in a inverse relationship with the kappa and u(H(+)) values. The proton transport depends strongly on the DeltaE(int) in the membranes.
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Affiliation(s)
- Morihiro Saito
- National Institute of Advanced Industrial Science and Technology, AIST Tsukuba Center 5, Ibaraki 305-8565, Japan
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Xue S, Yin G. Proton exchange membranes based on modified sulfonated poly(ether ether ketone) membranes with chemically in situ polymerized polypyrrole. Electrochim Acta 2006. [DOI: 10.1016/j.electacta.2006.06.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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