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Influence of highly flexible di(biphenyl)ethane units on the properties of poly(arylene piperidinium) anion exchange membranes

Chen, Si LU ; Xia, Yifan ; Aili, David and Jannasch, Patric LU orcid (2025) In Journal of Materials Chemistry A
Abstract
Introducing angled arene units or short flexible alkyl segments into rigid aromatic hetero-atom-free polymer backbones is an efficient strategy to improve the performance of anion exchange membranes (AEM)s. So far, only very few monomers have been presented that increase backbone flexibility in polymers prepared by polyhydroxyalkylations, often with limited reactivity and polymerizability. Here, we present the synthesis of a highly reactive monomer [m-di(biphenyl)ethane, mD] containing two angled biphenyl units bridged by an ethane link using a straightforward noble-catalyst-free reductive homocoupling reaction. A series of copolymers were prepared by polyhydroxyalkylation of p-terphenyl, N-methylpiperidone, and... (More)
Introducing angled arene units or short flexible alkyl segments into rigid aromatic hetero-atom-free polymer backbones is an efficient strategy to improve the performance of anion exchange membranes (AEM)s. So far, only very few monomers have been presented that increase backbone flexibility in polymers prepared by polyhydroxyalkylations, often with limited reactivity and polymerizability. Here, we present the synthesis of a highly reactive monomer [m-di(biphenyl)ethane, mD] containing two angled biphenyl units bridged by an ethane link using a straightforward noble-catalyst-free reductive homocoupling reaction. A series of copolymers were prepared by polyhydroxyalkylation of p-terphenyl, N-methylpiperidone, and different concentrations of mD. Small angle X-ray scattering analysis of the AEMs indicated enhanced ionic clustering with increasing mD content and backbone flexibility. Moreover, water and KOH (aq.) uptake, hydroxide conductivity and alkaline stability increased with the mD content. The hydroxide conductivity of an AEM containing 25% mD units reached 187 mS cm-1 at 80 °C in water, and an AEM with 50% mD units exhibited a conductivity of 53 mS cm-1 in 2 M KOH (aq.) solution. Using only simple nickel foam electrodes, the latter AEM reached a current density of >400 mA cm-2 at 2.5 V without any cell optimization. In summary, this work demonstrates a convenient synthetic strategy to incorporate flexible units in rigid aromatic polymers prepared by polyhydroxyalkylation, offering improved membrane properties and valuable insights into the design and optimization of advanced AEM materials.
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publication status
epub
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in
Journal of Materials Chemistry A
publisher
Royal Society of Chemistry
ISSN
2050-7488
DOI
10.1039/D5TA04171F
language
English
LU publication?
yes
id
561f6139-b5ad-4c23-b3ce-37184e7f6734
date added to LUP
2024-11-18 18:54:16
date last changed
2025-08-25 13:42:37
@article{561f6139-b5ad-4c23-b3ce-37184e7f6734,
  abstract     = {{Introducing angled arene units or short flexible alkyl segments into rigid aromatic hetero-atom-free polymer backbones is an efficient strategy to improve the performance of anion exchange membranes (AEM)s. So far, only very few monomers have been presented that increase backbone flexibility in polymers prepared by polyhydroxyalkylations, often with limited reactivity and polymerizability. Here, we present the synthesis of a highly reactive monomer [<i>m</i>-di(biphenyl)ethane,<i> m</i>D] containing two angled biphenyl units bridged by an ethane link using a straightforward noble-catalyst-free reductive homocoupling reaction. A series of copolymers were prepared by polyhydroxyalkylation of <i>p</i>-terphenyl, <i>N</i>-methylpiperidone, and different concentrations of <i>m</i>D. Small angle X-ray scattering analysis of the AEMs indicated enhanced ionic clustering with increasing <i>m</i>D content and backbone flexibility. Moreover, water and KOH (aq.) uptake, hydroxide conductivity and alkaline stability increased with the <i>m</i>D content. The hydroxide conductivity of an AEM containing 25% <i>m</i>D units reached 187 mS cm<sup>-1</sup> at 80 °C in water, and an AEM with 50% <i>m</i>D units exhibited a conductivity of 53 mS cm<sup>-1</sup> in 2 M KOH (aq.) solution. Using only simple nickel foam electrodes, the latter AEM reached a current density of &gt;400 mA cm<sup>-2</sup> at 2.5 V without any cell optimization. In summary, this work demonstrates a convenient synthetic strategy to incorporate flexible units in rigid aromatic polymers prepared by polyhydroxyalkylation, offering improved membrane properties and valuable insights into the design and optimization of advanced AEM materials.<br/>}},
  author       = {{Chen, Si and Xia, Yifan and Aili, David and Jannasch, Patric}},
  issn         = {{2050-7488}},
  language     = {{eng}},
  publisher    = {{Royal Society of Chemistry}},
  series       = {{Journal of Materials Chemistry A}},
  title        = {{Influence of highly flexible di(biphenyl)ethane units on the properties of poly(arylene piperidinium) anion exchange membranes}},
  url          = {{http://dx.doi.org/10.1039/D5TA04171F}},
  doi          = {{10.1039/D5TA04171F}},
  year         = {{2025}},
}