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Acidity effects of medium fluids on anhydrous proton conductivity of acid-swollen block polymer electrolyte membranes
Proton-conductive polymer electrolyte membranes (PEMs) were prepared by infiltrating sulfuric acid (Sa) or phosphoric acid (Pa) into a polystyrene-b-poly(4-vinylpyridine)-b-polystyrene (S–P–S) triblock copolymer. When the molar ratio of acid to pyridyl groups in S–P–S, i.e., the acid doping level (A...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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The Royal Society of Chemistry
2021
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9033556/ https://www.ncbi.nlm.nih.gov/pubmed/35478621 http://dx.doi.org/10.1039/d1ra01211h |
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author | Kajita, Takato Noro, Atsushi Seki, Takahiro Matsushita, Yushu Nakamura, Naoki |
author_facet | Kajita, Takato Noro, Atsushi Seki, Takahiro Matsushita, Yushu Nakamura, Naoki |
author_sort | Kajita, Takato |
collection | PubMed |
description | Proton-conductive polymer electrolyte membranes (PEMs) were prepared by infiltrating sulfuric acid (Sa) or phosphoric acid (Pa) into a polystyrene-b-poly(4-vinylpyridine)-b-polystyrene (S–P–S) triblock copolymer. When the molar ratio of acid to pyridyl groups in S–P–S, i.e., the acid doping level (ADL), is below unity, the P-block/acid phase in the PEMs exhibited a moderately high glass transition temperature (T(g)) of ∼140 °C because of consumption of acids for forming the acid–base complexes between the pyridyl groups and the acids, also resulting in almost no free protons in the PEMs; therefore, the PEMs were totally glassy and exhibited almost no anhydrous conductivity. In contrast, when ADL is larger than unity, the T(g)s of the phase composed of acid and P blocks were lower than room temperature, due to the excessive molar amount of acid serving as a plasticizer. Such swollen PEMs with excessive amounts of acid releasing free protons were soft and exhibited high conductivities even without humidification. In particular, an S–P–S/Sa membrane with ADL of 4.6 exhibited a very high anhydrous conductivity of 1.4 × 10(−1) S cm(−1) at 95 °C, which is comparable to that of humidified Nafion membranes. Furthermore, S–P–S/Sa membranes with lower T(g)s exhibited higher conductivities than S–P–S/Pa membranes, whereas the temperature dependence of the conductivities for S–P–S/Pa is stronger than that for S–P–S/Sa, suggesting Pa with a lower acidity would not be effectively dissociated into a dihydrogen phosphate anion and a free proton in the PEMs at lower temperatures. |
format | Online Article Text |
id | pubmed-9033556 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | The Royal Society of Chemistry |
record_format | MEDLINE/PubMed |
spelling | pubmed-90335562022-04-26 Acidity effects of medium fluids on anhydrous proton conductivity of acid-swollen block polymer electrolyte membranes Kajita, Takato Noro, Atsushi Seki, Takahiro Matsushita, Yushu Nakamura, Naoki RSC Adv Chemistry Proton-conductive polymer electrolyte membranes (PEMs) were prepared by infiltrating sulfuric acid (Sa) or phosphoric acid (Pa) into a polystyrene-b-poly(4-vinylpyridine)-b-polystyrene (S–P–S) triblock copolymer. When the molar ratio of acid to pyridyl groups in S–P–S, i.e., the acid doping level (ADL), is below unity, the P-block/acid phase in the PEMs exhibited a moderately high glass transition temperature (T(g)) of ∼140 °C because of consumption of acids for forming the acid–base complexes between the pyridyl groups and the acids, also resulting in almost no free protons in the PEMs; therefore, the PEMs were totally glassy and exhibited almost no anhydrous conductivity. In contrast, when ADL is larger than unity, the T(g)s of the phase composed of acid and P blocks were lower than room temperature, due to the excessive molar amount of acid serving as a plasticizer. Such swollen PEMs with excessive amounts of acid releasing free protons were soft and exhibited high conductivities even without humidification. In particular, an S–P–S/Sa membrane with ADL of 4.6 exhibited a very high anhydrous conductivity of 1.4 × 10(−1) S cm(−1) at 95 °C, which is comparable to that of humidified Nafion membranes. Furthermore, S–P–S/Sa membranes with lower T(g)s exhibited higher conductivities than S–P–S/Pa membranes, whereas the temperature dependence of the conductivities for S–P–S/Pa is stronger than that for S–P–S/Sa, suggesting Pa with a lower acidity would not be effectively dissociated into a dihydrogen phosphate anion and a free proton in the PEMs at lower temperatures. The Royal Society of Chemistry 2021-05-26 /pmc/articles/PMC9033556/ /pubmed/35478621 http://dx.doi.org/10.1039/d1ra01211h Text en This journal is © The Royal Society of Chemistry https://creativecommons.org/licenses/by-nc/3.0/ |
spellingShingle | Chemistry Kajita, Takato Noro, Atsushi Seki, Takahiro Matsushita, Yushu Nakamura, Naoki Acidity effects of medium fluids on anhydrous proton conductivity of acid-swollen block polymer electrolyte membranes |
title | Acidity effects of medium fluids on anhydrous proton conductivity of acid-swollen block polymer electrolyte membranes |
title_full | Acidity effects of medium fluids on anhydrous proton conductivity of acid-swollen block polymer electrolyte membranes |
title_fullStr | Acidity effects of medium fluids on anhydrous proton conductivity of acid-swollen block polymer electrolyte membranes |
title_full_unstemmed | Acidity effects of medium fluids on anhydrous proton conductivity of acid-swollen block polymer electrolyte membranes |
title_short | Acidity effects of medium fluids on anhydrous proton conductivity of acid-swollen block polymer electrolyte membranes |
title_sort | acidity effects of medium fluids on anhydrous proton conductivity of acid-swollen block polymer electrolyte membranes |
topic | Chemistry |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9033556/ https://www.ncbi.nlm.nih.gov/pubmed/35478621 http://dx.doi.org/10.1039/d1ra01211h |
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