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Srivastav H, Weber AZ, Radke CJ. Colloidal Stability of PFSA-Ionomer Dispersions. Part I. Single-Ion Electrostatic Interaction Potential Energies. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:6654-6665. [PMID: 38457278 DOI: 10.1021/acs.langmuir.3c03903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/10/2024]
Abstract
Charged colloidal particles neutralized by a single counterion are increasingly important for many emerging technologies. Attention here is paid specifically to hydrogen fuel cells and water electrolyzers whose catalyst layers are manufactured from a perfluorinated sulfonic acid polymer (PFSA) suspended in aqueous/alcohol solutions. Partially dissolved PFSA aggregates, known collectively as ionomers, are stabilized by the electrostatic repulsion of overlapping diffuse double layers consisting of only protons dissociated from the suspended polymer. We denote such double layers containing no added electrolyte as "single ion". Size-distribution predictions build upon interparticle interaction potential energies from the Derjaguin-Landau-Verwey-Overbeek (DLVO) formalism. However, when only a single counterion is present in solution, classical DLVO electrostatic potential energies no longer apply. Accordingly, here a new formulation is proposed to describe how single-counterion diffuse double layers interact in colloidal suspensions. Part II (Srivastav, H.; Weber, A. Z.; Radke, C. J. Langmuir 2024 DOI: 10.1021/acs.langmuir.3c03904) of this contribution uses the new single-ion interaction energies to predict aggregated size distributions and the resulting solution pH of PFSA in mixtures of n-propanol and water. A single-counterion diffuse layer cannot reach an electrically neutral concentration far from a charged particle. Consequently, nowhere in the dispersion is the solvent neutral, and the diffuse layer emanating from one particle always experiences the presence of other particles (or walls). Thus, in addition to an intervening interparticle repulsive force, a backside osmotic force is always present. With this new construction, we establish that single-ion repulsive pair interaction energies are much larger than those of classical DLVO electrostatic potentials. The proposed single-ion electrostatic pair potential governs dramatic new dispersion behavior, including dispersions that are stable at a low volume fraction but unstable at a high volume fraction and finite volume-fraction dispersions that are unstable with fine particles but stable with coarse particles. The proposed single-counterion electrostatic pair potential provides a general expression for predicting colloidal behavior for any charged particle dispersion in ionizing solvents with no added electrolyte.
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Affiliation(s)
- Harsh Srivastav
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, 201 Gilman, South Drive, Berkeley, California 94720, United States
- Energy Technologies Area, Lawrence Berkeley National Laboratory, Building 30, Cyclotron Road, Berkeley, California 94720, United States
| | - Adam Z Weber
- Energy Technologies Area, Lawrence Berkeley National Laboratory, Building 30, Cyclotron Road, Berkeley, California 94720, United States
| | - Clayton J Radke
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, 201 Gilman, South Drive, Berkeley, California 94720, United States
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Klein JM, Welch C, Ponnurangam S, Tarokh A, Karan K, Hawley ME, Sokolova A, Yim SD, Hjelm RP, Kim YS. Colloidal Nafion Particles: Are Cylinders Ubiquitous? ACS Macro Lett 2023; 12:1648-1653. [PMID: 37987786 DOI: 10.1021/acsmacrolett.3c00616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Colloidal Nafion morphology plays a critical role in determining the performance of fuel cells and electrolyzers. While small-angle neutron scattering (SANS) studies previously described Nafion in liquid media as dispersed cylinders, the analysis remains nonunique with multiple possible morphological descriptions of the data. Here, using SANS and all-atomistic molecular dynamics, we confirm that Nafion morphology in liquid media differs substantially depending on dispersing agent and dispersion method. H+ Nafion dispersed in N-methyl pyrrolidone forms swollen cluster particles with physically cross-linked ionic groups. Scattering profiles from dispersed Nafion membrane have a large structure factor feature not observed for redispersed Nafion D-521. H+ Nafion dispersed in water has a highly elongated cylindrical morphology (radius = 10 ± 1.5 Å, height = 358 ± 4.7 Å) with fully dissociated and solvated sulfonic acid groups on the particle wall. These results highlight an important discrepancy between the methods of preparing Nafion dispersions and the use of simplified analysis techniques to describe Nafion morphology.
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Affiliation(s)
- Jeffrey M Klein
- MPA-11: Materials Synthesis and Integrated Devices, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Cynthia Welch
- Engineered Materials Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Sathish Ponnurangam
- Department of Chemical and Petroleum Engineering, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N In4, Canada
| | - Atefeh Tarokh
- Department of Chemical and Petroleum Engineering, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N In4, Canada
| | - Kunal Karan
- Department of Chemical and Petroleum Engineering, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N In4, Canada
| | - Marilyn E Hawley
- MST-8: Materials at Extremes, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Anna Sokolova
- Australian Center for Neutron Science, Australian National Science and Technology Organization (ANSTO), Lucas Heights, NSW 2234, Australia
| | - Sung-Dae Yim
- Fuel Cell Laboratory, Korea Institute of Energy Research, Daejeon 34129, Korea
| | - Rex P Hjelm
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, and the New Mexico Consortium, Los Alamos, New Mexico 87545, United States
| | - Yu Seung Kim
- MPA-11: Materials Synthesis and Integrated Devices, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
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Li G, Zhu Y, Guo Y, Mabuchi T, Li D, Huang S, Wang S, Sun H, Tokumasu T. Deep Learning to Reveal the Distribution and Diffusion of Water Molecules in Fuel Cell Catalyst Layers. ACS APPLIED MATERIALS & INTERFACES 2023; 15:5099-5108. [PMID: 36652634 DOI: 10.1021/acsami.2c17198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Water management in the catalyst layers (CLs) of proton-exchange membrane fuel cells is crucial for its commercialization and popularization. However, the high experimental or computational cost in obtaining water distribution and diffusion remains a bottleneck in the existing experimental methods and simulation algorithms, and further mechanistic exploration at the nanoscale is necessary. Herein, we integrate, for the first time, molecular dynamics simulation with our customized analysis framework based on a multiattribute point cloud dataset and an advanced deep learning network. This was achieved through our workflow that generates simulated transport data of water molecules in the CLs as the training and test dataset. Deep learning framework models the multibody solid-liquid system of CLs on a molecular scale and completes the mapping from the Pt/C substrate structure and Nafion aggregates to the density distribution and diffusion coefficient of water molecules. The prediction results are comprehensively analyzed and error evaluated, which reveals the highly anisotropic interaction landscape between 50,000 pairs of interacting nanoparticles and explains the structure and water transport property relationship in the hydrated Nafion film on the molecular scale. Compared to the conventional methods, the proposed deep learning framework shows computational cost efficiency, accuracy, and good visual display. Further, it has a generality potential to model macro- and microscopic mass transport in different components of fuel cells. Our framework is expected to make real-time predictions of the distribution and diffusion of water molecules in CLs as well as establish statistical significance in the structural optimization and design of CLs and other components of fuel cells.
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Affiliation(s)
- Gaoyang Li
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai980-8577, Japan
| | - Yonghong Zhu
- School of Chemical Engineering, Northwest University, Xi'an710069Shaanxi, China
| | - Yuting Guo
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai980-8577, Japan
| | - Takuya Mabuchi
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai980-8577, Japan
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi980-8577, Japan
| | - Dong Li
- School of Chemical Engineering, Northwest University, Xi'an710069Shaanxi, China
| | - Shengfeng Huang
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai980-8577, Japan
| | - Sirui Wang
- Graduate School of Engineering, Chiba University, 1-33, Yayoi-cho, Inage-ku, Chiba263-8522, Japan
| | - Haiyi Sun
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai980-8577, Japan
| | - Takashi Tokumasu
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai980-8577, Japan
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Mabuchi T, Kijima J, Yamashita Y, Miura E, Muraoka T. Coacervate Formation of Elastin-like Polypeptides in Explicit Aqueous Solution Using Coarse-Grained Molecular Dynamics Simulations. Macromolecules 2023. [DOI: 10.1021/acs.macromol.2c02195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Takuya Mabuchi
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai, Miyagi980-8577, Japan
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai, Miyagi980-8577, Japan
| | - Junko Kijima
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai, Miyagi980-8577, Japan
| | - Yukino Yamashita
- Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho,
Koganei, Tokyo184-8588, Japan
| | - Erika Miura
- Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho,
Koganei, Tokyo184-8588, Japan
| | - Takahiro Muraoka
- Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho,
Koganei, Tokyo184-8588, Japan
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Guo Y, Mabuchi T, Li G, Tokumasu T. Morphology Evolution and Adsorption Behavior of Ionomers from Solution to Pt/C Substrates. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c00533] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yuting Guo
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai 980-8577, Japan
| | - Takuya Mabuchi
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai 980-8577, Japan
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 2-1-1 Katahira Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Gaoyang Li
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai 980-8577, Japan
| | - Takashi Tokumasu
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai 980-8577, Japan
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Guo Y, Li G, Mabuchi T, Surblys D, Ohara T, Tokumasu T. Prediction of nanoscale thermal transport and adsorption of liquid containing surfactant at solid–liquid interface via deep learning. J Colloid Interface Sci 2022; 613:587-596. [DOI: 10.1016/j.jcis.2022.01.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 01/04/2022] [Accepted: 01/06/2022] [Indexed: 10/19/2022]
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Prediction of the adsorption properties of liquid at solid surfaces with molecular scale surface roughness via encoding-decoding convolutional neural networks. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.118489] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Michelarakis N, Franz F, Gkagkas K, Gräter F. Longitudinal strand ordering leads to shear thinning in Nafion. Phys Chem Chem Phys 2021; 23:25901-25910. [PMID: 34779459 DOI: 10.1039/d1cp02024b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Proton-exchange membrane fuel cells (PEMFC) offer a promising energy generation alternative for a wide range of technologies thanks to their ecological friendliness and unparalleled efficiency. At the heart of these electrochemical cells lies the membrane electrode assembly with its most important energy conversion components, the Proton Exchange Membrane. This component is created through the use of printing techniques and Nafion inks. The physicochemical properties of the ink, such as its viscosity under shear, are critical for the finished product. In this work we present non-equilibrium Molecular Dynamics simulations using a MARTINI based coarse-grained model for Nafion to understand the mechanism governing the shear viscosity of Nafion solutions. By simulating a Couette flow and calculating density maps of the Nafion chains in these simulations we shed light on the process that leads to the experimentally observed shear thinning effects of Nafion solutions under flow. We observe rod-shaped Nafion microstructures, 3 nm in size on average, when shear flow is absent or low. Higher shear rates instead break these structures and align Nafion strands along the direction of the flow, resulting in lower shear viscosities. Our work paves the way for a deeper understanding of the dynamic and mechanical properties of Nafion including studies of more complex CL and PEM inks.
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Affiliation(s)
- Nicholas Michelarakis
- Molecular Biomechanics Group, Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118 Heidelberg, Germany
| | - Florian Franz
- Molecular Biomechanics Group, Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118 Heidelberg, Germany
| | - Konstantinos Gkagkas
- Toyota Motor Europe, Technical Center, Toyota Motor Europe NVSA, Zavente, Belgium
| | - Frauke Gräter
- Molecular Biomechanics Group, Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118 Heidelberg, Germany.,Interdisciplinary Center for Scientific Computing, Heidelberg University, INF 205, 69120 Heidelberg, Germany
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Alessandri R, Grünewald F, Marrink SJ. The Martini Model in Materials Science. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2008635. [PMID: 33956373 DOI: 10.1002/adma.202008635] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 03/15/2021] [Indexed: 06/12/2023]
Abstract
The Martini model, a coarse-grained force field initially developed with biomolecular simulations in mind, has found an increasing number of applications in the field of soft materials science. The model's underlying building block principle does not pose restrictions on its application beyond biomolecular systems. Here, the main applications to date of the Martini model in materials science are highlighted, and a perspective for the future developments in this field is given, particularly in light of recent developments such as the new version of the model, Martini 3.
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Affiliation(s)
- Riccardo Alessandri
- Zernike Institute for Advanced Materials and Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, Groningen, 9747AG, The Netherlands
| | - Fabian Grünewald
- Zernike Institute for Advanced Materials and Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, Groningen, 9747AG, The Netherlands
| | - Siewert J Marrink
- Zernike Institute for Advanced Materials and Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, Groningen, 9747AG, The Netherlands
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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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Mabuchi T, Huang SF, Tokumasu T. Influence of Ionomer Loading and Substrate Wettability on the Morphology of Ionomer Thin Films Using Coarse-Grained Solvent Evaporation Simulations. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c01303] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Takuya Mabuchi
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Sheng-Feng Huang
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Takashi Tokumasu
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai, Miyagi 980-8577, Japan
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12
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Mabuchi T, Huang SF, Tokumasu T. Dispersion of Nafion Ionomer Aggregates in 1-Propanol/Water Solutions: Effects of Ionomer Concentration, Alcohol Content, and Salt Addition. Macromolecules 2020. [DOI: 10.1021/acs.macromol.9b02725] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Takuya Mabuchi
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 2-1-1 Katahira Aoba-ku, Sendai, Miyagi 980-8577, Japan
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Sheng-Feng Huang
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Takashi Tokumasu
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira Aoba-ku, Sendai, Miyagi 980-8577, Japan
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