Phosphonium-functionalized polyethylene: A new class of base-stable alkaline anion exchange membranes

Abstract

A tetrakis(dialkylamino)phosphonium cation was evaluated as a functional group for alkaline anion exchange membranes (AAEMs). The base stability of [P(N(Me)Cy) 4] + was directly compared to that of [BnNMe 3] + in 1 M NaOD/CD 3OD. The high base stability of [P(N(Me)Cy) 4] + relative to [BnNMe 3] + inspired the preparation of AAEM materials composed of phosphonium units attached to polyethylene. The AAEMs (hydroxide conductivity of 22 ± 1 mS cm -1 at 22 °C) were prepared using ring-opening metathesis polymerization, and their stabilities were evaluated in 15 M KOH at 22 °C and in 1 M KOH at 80 °C. © 2012 American Chemical Society.