Blend membranes based on N1-alkyl-substituted imidazolium functionalized polymers and aromatic polyethers: influence of N1-alkyl substituent on properties and alkaline stability

Tsagdi, Artemis; Dimitriou, Michael; Druvari, Denisa; Deimede, Valadoula

doi:10.1007/s00289-021-03581-5

Cited by 3 publications

(1 citation statement)

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“…After cationic functionalization, the broad peak observed at 3400 cm −1 was attributed to the characteristic stretching vibration of -OH groups of water molecules due to the hydrophilicity of cationic groups [ 40 ]. Two new absorption peaks arose at 2925 and 2860 cm −1 that are assigned to the stretching vibrations of methyl and methylene groups of alkyl spacer, respectively [ 41 ]. Therefore, these results in combination with the new peak observed at 1351 cm −1 corresponding to the stretching vibration of C-N + , confirm the successful incorporation of long side chain quaternized groups onto the polymeric backbone.…”

Section: Resultsmentioning

confidence: 99%

Cycloaliphatic Quaternary Ammonium Functionalized Poly(oxindole biphenyl) Based Anion-Exchange Membranes for Water Electrolysis: Stability and Performance

Gjoshi,

Loukopoulou,

Plevova

et al. 2023

Polymers

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Mechanically robust anion-exchange membranes (AEMs) with high conductivity and long-term alkali resistance are needed for water electrolysis application. In this work, aryl-ether free polyaromatics containing isatin moieties were prepared via super acid-catalyzed copolymerization, followed by functionalization with alkaline stable cyclic quaternary ammonium (QA) cationic groups, to afford high performance AEMs for application in water electrolysis. The incorporation of side functional cationic groups (pyrrolidinium and piperidinium) onto a polymer backbone via a flexible alkyl spacer aimed at conductivity and alkaline stability improvement. The effect of cation structure on the properties of prepared AEMs was thoroughly studied. Pyrrolidinium- and piperidinium-based AEMs showed similar electrolyte uptakes and no obvious phase separation, as revealed by SAXS and further supported by AFM and TEM data. In addition, these AEMs displayed high conductivity values (81. 5 and 120 mS cm−1 for pyrrolidinium- and piperidinium-based AEM, respectively, at 80 °C) and excellent alkaline stability after 1 month aging in 2M KOH at 80 °C. Especially, a pyrrolidinium-based AEM membrane preserved 87% of its initial conductivity value, while at the same time retaining its flexibility and mechanical robustness after storage in alkaline media (2M KOH) for 1 month at 80 °C. Based on 1H NMR data, the conductivity loss observed after the aging test is mainly related to the piperidinium degradation that took place, probably via ring-opening Hofmann elimination, alkyl spacer scission and nucleophilic substitution reactions as well. The synthesized AEMs were also tested in an alkaline water electrolysis cell. Piperidinium-based AEM showed superior performance compared to its pyrrolidinium analogue, owing to its higher conductivity as revealed by EIS data, further confirming the ex situ conductivity measurements.

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Section: Resultsmentioning

confidence: 99%