Angela Mohanty - Systematic Alkaline Stability Study of Polymer Backbones for Anion Exchange Membrane Applications

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Mohanty, A.D.; Tignor, S.E.; Krause, J.A.; Choe, Y-K; Bae, C., Systematic Alkaline Stability Study of Polymer Backbones for Anion Exchange Membrane Applications, Macromolecules, 2016, 49, 3361


 Anion exchange membranes are an important component in alkaline electrochemical energy conversion and

storage devices, and their alkaline stability plays a crucial role for the long-term use of these devices. Herein, a systematic study

was conducted for the analysis of polymer backbone chemical stability in alkaline media. Nine representative polymer structures

including poly(arylene ether)s, poly(biphenyl alkylene)s, and polystyrene block copolymers were investigated for their alkaline

stability. Polymers with aryl ether bonds in their repeating unit showed poor chemical stability when treated with KOH and

NaOCH solutions, whereas polymers without aryl ether bonds [e.g., poly(biphenyl alkylene)s and polystyrene block

copolymers] remained stable. Additional NMR studies and density functional theory (DFT) calculations of small molecule

model compounds that mimic the chemical structures of poly(arylene ether)s confi rmed that electron-withdrawing groups near

to the aryl ether bonds in the repeating unit accelerate chemical degradation. Results from this study suggest that the use of allcarbon-

based polymer repeating units (i.e., polymers not bearing aryl ether bonds) can enhance long-term alkaline stability of


anion exchange membranes in electrochemical energy devices.

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