• anion exchange membrane;
  • quaternary phosphonism;
  • hydroxide conductivity;
  • fuel cell


Quaternary phosphonium-based polyelectrolyte was synthesized from bromomethylated poly(2,6-dimethyl-1,4- phenylene oxide) (BPPO) by functionalization with tris(2,4,6-trimethoxyphenyl) phosphine (TTMPP). Typically, excellent solubility of the polyelectrolyte in polar solvents, such as NMP and DMSO, allowed a solution-casting strategy for preparation of anion exchange membrane (AEM) with properly ordered hydrophilic/hydrophobic nano-scale phase separation morphology, which was visible in atomic force microscopic phase images. Accordingly, the optimized ionmeric AEM exhibited excellent hydroxide conductivity of 110 mS/cm at 70°C, but extremely restricted linear expansion ratio of below 7% at the same temperature. Additionally, such membrane could maintain flexibility and conductivity after an immersion treatment in 1 mol/L NaOH solution at 60°C for about 100 h, implying its potential in alkaline fuel cells.