Hydrophobic comb quaternary ammonium-functionalized poly(2,6-dimethyl- 1,4-phenylene oxide) (AQA-PPOs) having long alkyl side chains were prepared as novel anion exchange membranes. The effects of the relative number of alkyl side chains in the polymer on the conductivity, alkaline stability and other physicochemical properties of the corresponding AQA-PPO membranes were also investigated. The membranes made with more alkyl groups displayed greater conductivity and alkaline stability, and this result was attributed to the increased water uptake of these membranes. The A11QA37-PPO membrane, which had the highest alkyl group content, showed a conductivity as high as 46.0 mS cm-1 at 20°C and 101.9 mS cm-1 at 80°C with an IEC of only 1.92 meq g-1.