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Polymers functionalised with aliphatic mono- and spirocyclic quaternary ammonium cations for anion exchange membranes

Olsson, Joel LU ; Pham, Thanh Huong LU ; Dang, Hai-Son LU and Jannasch, Patric LU (2017) Workshop on Ion Exchange Membranes for Energy Applications, EMEA2017
Abstract
Different approaches to anion exchange membranes (AEMs) are currently intensively investigated with the aim to develop materials for application in electrochemical energy devices such as alkaline fuel cells and electrolysers.1 One of the major challenges is to identify feasible synthetic strategies to AEM materials with sufficient long-term chemical and thermal stability. Studies of different small cationic model compounds have revealed that aliphatic mono- and spirocyclic quaternary ammonium (QA) cations have a very high alkaline stability, most probably because the constrained ring conformations increase the transition state energy of the degradation reactions.2

Our research group has previously reported on the functionalisation... (More)
Different approaches to anion exchange membranes (AEMs) are currently intensively investigated with the aim to develop materials for application in electrochemical energy devices such as alkaline fuel cells and electrolysers.1 One of the major challenges is to identify feasible synthetic strategies to AEM materials with sufficient long-term chemical and thermal stability. Studies of different small cationic model compounds have revealed that aliphatic mono- and spirocyclic quaternary ammonium (QA) cations have a very high alkaline stability, most probably because the constrained ring conformations increase the transition state energy of the degradation reactions.2

Our research group has previously reported on the functionalisation of poly(phenylene oxide) (PPO) with different QA cations attached via flexible alkyl spacers.3 Recently, we have also studied PPO tethered with various cyclo-aliphatic QA cations. The results indicated that pyrrolidinium and piperidinium displayed excellent stability (1 M NaOH, 90 °C), while larger rings without severe conformational constraints (azepanium) and rings containing additional heteroatoms (morpholinium) readily degraded under the same conditions. In addition, we have investigated poly(arylene ether sulfone)s functionalised with bis-N-spirocyclic QA moieties along the backbone.4 AEMs based on these polymers reached high OH– conductivity, but were found to degrade under alkaline conditions at elevated temperatures. This motivated us to design and synthesize alternative N-spirocyclic structures based on poly(N,N-diallylazacycloalkane)s5 and N-spirocyclic quaternary ammonium ionenes6 (“spiro-ionenes”), respectively, all without any chemically sensitive ether bridges. The approach significantly improved the stability of this novel class of materials. In the current presentation we will discuss molecular design principles, synthetic procedures and important structure-property relationships of these new AEM materials. (Less)
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Workshop on Ion Exchange Membranes for Energy Applications, EMEA2017
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English
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f2c99167-914d-4848-9840-a04ee59925b5
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2017-06-29 22:06:33
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@misc{f2c99167-914d-4848-9840-a04ee59925b5,
  abstract     = {Different approaches to anion exchange membranes (AEMs) are currently intensively investigated with the aim to develop materials for application in electrochemical energy devices such as alkaline fuel cells and electrolysers.1 One of the major challenges is to identify feasible synthetic strategies to AEM materials with sufficient long-term chemical and thermal stability. Studies of different small cationic model compounds have revealed that aliphatic mono- and spirocyclic quaternary ammonium (QA) cations have a very high alkaline stability, most probably because the constrained ring conformations increase the transition state energy of the degradation reactions.2<br/><br/>Our research group has previously reported on the functionalisation of poly(phenylene oxide) (PPO) with different QA cations attached via flexible alkyl spacers.3 Recently, we have also studied PPO tethered with various cyclo-aliphatic QA cations. The results indicated that pyrrolidinium and piperidinium displayed excellent stability (1 M NaOH, 90 °C), while larger rings without severe conformational constraints (azepanium) and rings containing additional heteroatoms (morpholinium) readily degraded under the same conditions. In addition, we have investigated poly(arylene ether sulfone)s functionalised with bis-N-spirocyclic QA moieties along the backbone.4 AEMs based on these polymers reached high OH– conductivity, but were found to degrade under alkaline conditions at elevated temperatures. This motivated us to design and synthesize alternative N-spirocyclic structures based on poly(N,N-diallylazacycloalkane)s5 and N-spirocyclic quaternary ammonium ionenes6 (“spiro-ionenes”), respectively, all without any chemically sensitive ether bridges. The approach significantly improved the stability of this novel class of materials. In the current presentation we will discuss molecular design principles, synthetic procedures and important structure-property relationships of these new AEM materials.},
  author       = {Olsson, Joel and Pham, Thanh Huong and Dang, Hai-Son and Jannasch, Patric},
  language     = {eng},
  title        = {Polymers functionalised with aliphatic mono- and spirocyclic quaternary ammonium cations for anion exchange membranes},
  year         = {2017},
}