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Schiavone MM, Lamparelli DH, Daniel C, Golla M, Zhao Y, Iwase H, Arima-Osonoi H, Takata SI, Szentmiklosi L, Maroti B, Allgaier J, Radulescu A. Extended Q-range small-angle neutron scattering to understand the morphology of proton-exchange membranes: the case of the functionalized syndiotactic-polystyrene model system. J Appl Crystallogr 2023; 56:947-960. [PMID: 37555213 PMCID: PMC10405591 DOI: 10.1107/s1600576723005496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Accepted: 06/21/2023] [Indexed: 08/10/2023] Open
Abstract
Semi-crystalline polymers exhibit microphase separation into crystalline and amorphous domains characterized by multiple structural levels with sizes ranging from ångströms to hundreds of nanometres. The combination of small-angle (SANS) and wide-angle (WANS) neutron scattering on the same beamline enables reliable in situ characterization of such materials under application-relevant conditions, with the unique advantage of contrast variation by controlled labelling, allowing the structure of such multi-component systems to be resolved in detail. This paper reports a structural analysis performed on deuterated polymer membranes based on syndiotactic polystyrene (sPS) using an extended Q-range SANS and WANS combination, always with the same neutron scattering instrument, either a pinhole SANS diffractometer installed at a research reactor or a 'small- and wide-angle' time-of-flight diffractometer installed at a neutron spallation source. sPS is a semi-crystalline material that becomes hydrophilic and proton conducting when suitable functionalization is achieved by thin film sulfonation, and can form various co-crystalline complexes (clathrates) with small organic molecules stored in the crystalline phase as guests in the vacancies between the polymer helices. Therefore, this material is interesting not only for its conducting properties but also for its versatility as a model system to evaluate the usefulness of extended Q-range neutron scattering in such studies. Variation of neutron contrast was achieved in the amorphous hydrophilic phase by using H2O or D2O to hydrate the membranes and in the crystalline phase by loading the clathrates with deuterated or protonated guest molecules. The experimental approach, the advantages and limitations of the two types of instrumentation used in such analyses, and the main results obtained with respect to the structural characterization of sulfonated sPS membranes under different hydration and temperature conditions are reported, and the potential of this method for similar structural studies on other semi-crystalline polymeric materials is discussed.
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Affiliation(s)
- Maria-Maddalena Schiavone
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstrasse 1, Garching, 85747, Germany
| | - David Hermann Lamparelli
- Dipartimento di Chimica e Biologia ‘Adolfo Zambelli’, Università di Salerno, Fisciano, I-84084, Italy
| | - Christophe Daniel
- Dipartimento di Chimica e Biologia ‘Adolfo Zambelli’, Università di Salerno, Fisciano, I-84084, Italy
| | - Manuchar Golla
- Dipartimento di Chimica e Biologia ‘Adolfo Zambelli’, Università di Salerno, Fisciano, I-84084, Italy
| | - Yue Zhao
- Takasaki Advanced Radiation Institute, National Institutes for Quantum Science and Technology, Takasaki, 370-1292, Japan
| | - Hiroki Iwase
- Neutron Science and Technology Centre, Comprehensive Research Organization for Science and Society CROSS, Tokai, 319-1106, Japan
| | - Hiroshi Arima-Osonoi
- Neutron Science and Technology Centre, Comprehensive Research Organization for Science and Society CROSS, Tokai, 319-1106, Japan
| | - Shin-ichi Takata
- Materials and Life Science Division, Japan Proton Accelerator Complex J-PARC, Tokai, 319-1195, Japan
| | - Laszlo Szentmiklosi
- Institute for Energy Security and Environmental Safety, Centre for Energy Research, Budapest, 1121, Hungary
| | - Boglarka Maroti
- Institute for Energy Security and Environmental Safety, Centre for Energy Research, Budapest, 1121, Hungary
| | - Jürgen Allgaier
- Jülich Centre for Neutron Science (JCNS), Forschungszentrum Jülich GmbH, Jülich, 52425, Germany
| | - Aurel Radulescu
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstrasse 1, Garching, 85747, Germany
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Schiavone MM, Zhao Y, Iwase H, Arima-Osonoi H, Takata SI, Radulescu A. On the Proton Conduction Pathways in Polyelectrolyte Membranes Based on Syndiotactic-Polystyrene. MEMBRANES 2022; 12:143. [PMID: 35207065 PMCID: PMC8878390 DOI: 10.3390/membranes12020143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 01/20/2022] [Accepted: 01/20/2022] [Indexed: 11/16/2022]
Abstract
When functionalized by the solid-state sulfonation process, the amorphous regions of the semi-crystalline syndiotactic-polystyrene (sPS) become hydrophilic, and thus can conduct protons upon membrane hydration, which increases the interest in this material as a potential candidate for applications with proton exchange membranes. The resistance of sulfonated sPS to oxidative decomposition can be improved by doping the membrane with fullerenes. In previous work, we have described the morphology in hydrated sulfonated sPS films doped with fullerenes on different length scales as determined by small-angle neutron scattering (SANS) and the structural changes in such membranes as a function of the degree of hydration and temperature. In the current work, we report on the relationship between the morphology of hydrated domains as obtained by SANS and the proton conductivity in sulfonated sPS-fullerene composite membranes at different temperature and relative humidity (RH) conditions. Based on this combined experimental approach, clear evidence for the formation and evolution of the hydrated domains in functionalized sPS membranes has been provided and a better understanding of the hydration and conductivity pathways in this material has been obtained.
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Affiliation(s)
| | - Yue Zhao
- Department of Advanced Functional Materials Research, Takasaki Advanced Radiation Research Institute, National Institutes for Quantum Science and Technology (QST), Watanuki-machi 1233, Takasaki 370-1292, Gunma, Japan;
| | - Hiroki Iwase
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS), 162-1 Shirakata, Tokai 319-1106, Ibaraki, Japan; (H.I.); (H.A.-O.)
| | - Hiroshi Arima-Osonoi
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS), 162-1 Shirakata, Tokai 319-1106, Ibaraki, Japan; (H.I.); (H.A.-O.)
| | - Shin-ichi Takata
- Materials and Life Science Division, Japan Proton Accelerator Research Complex (JPARC), Tokai 319-1195, Ibaraki, Japan;
| | - Aurel Radulescu
- Jülich Centre for Neutron Science, Forschungszentrum Jülich GmbH, 85748 Garching, Germany;
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Schiavone MM, Lamparelli DH, Zhao Y, Zhu F, Revay Z, Radulescu A. The Effects of Temperature and Humidity on the Microstructure of Sulfonated Syndiotactic-polystyrene Ionic Membranes. MEMBRANES 2020; 10:E187. [PMID: 32824025 PMCID: PMC7466101 DOI: 10.3390/membranes10080187] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/09/2020] [Accepted: 08/12/2020] [Indexed: 11/16/2022]
Abstract
Polymeric membranes based on the semi-crystalline syndiotactic-polystyrene (sPS) become hydrophilic, and therefore conductive, following the functionalization of the amorphous phase by the solid-state sulfonation procedure. Because the crystallinity of the material, and thus the mechanical strength of the membranes, is maintained and the resistance to oxidation decomposition can be improved by doping the membranes with fullerenes, the sPS becomes attractive for proton-exchange membranes fuel cells (PEMFC) and energy storage applications. In the current work we report the micro-structural characterization by small-angle neutron scattering (SANS) method of sulfonated sPS films and sPS-fullerene composite membranes at different temperatures between 20 °C and 80 °C, under the relative humidity (RH) level from 10% to 70%. Complementary characterization of membranes was carried out by FTIR, UV-Vis spectroscopy and prompt-γ neutron activation analysis in terms of composition, following the specific preparation and functionalization procedure, and by XRD with respect to crystallinity. The hydrated ionic clusters are formed in the hydrated membrane and shrink slightly with the increasing temperature, which leads to a slight desorption of water at high temperatures. However, it seems that the conductive properties of the membranes do not deteriorate with the increasing temperature and that all membranes equilibrated in liquid water show an increased conductivity at 80 °C compared to the room temperature. The presence of fullerenes in the composite membrane induces a tremendous increase in the conductivity at high temperatures compared to fullerenes-free membranes. Apparently, the observed effects may be related to the formation of additional hydrated pathways in the composite membrane in conjunction with changes in the dynamics of water and polymer.
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Affiliation(s)
- Maria-Maddalena Schiavone
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), 85747 Garching, Germany; (M.-M.S.); (F.Z.)
| | - David Hermann Lamparelli
- Dipartimento di Chimica e Biologia “Adolfo Zambelli”, Università di Salerno, I-84084 Fisciano, Italy;
| | - Yue Zhao
- Department of Advanced Functional Materials Research, Takasaki Advanced Radiation Research Institute, National Institutes for Quantum and Radiological Science and Technology (QST), Watanuki-machi 1233, Takasaki 370-1292, Japan;
| | - Fengfeng Zhu
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), 85747 Garching, Germany; (M.-M.S.); (F.Z.)
| | - Zsolt Revay
- Technische Universität Müchen, Forschungsneutronenquelle Heinz Maier-Leibnitz FRM II, Heinz Maier-Leibnitz Zentrum (MLZ), 85747 Garching, Germany;
| | - Aurel Radulescu
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), 85747 Garching, Germany; (M.-M.S.); (F.Z.)
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