Quaternized polyethersulfone Cardo anion exchange membranes for direct methanol alkaline fuel cells

A novel anion exchange membrane, quaternized polyethersulfone Cardo, was prepared. Polyethersulfone Cardo was chloromethylated with the complex solution of chloromethylether and chloride zinc. Subsequent reaction with trimethylamine and ion exchange with sodium hydroxide yields alkaline anion exchange membrane. The quaternized polyethersulfone Cardo (QPES-C) membrane may be suitable for use in low temperature direct methanol alkaline fuel cells. Ionic conductivity and methanol permeability of such membrane as a function of temperature were investigated. Ionic conductivity of QPES-C membrane in 1 M NaOH solution was 4.1 × 10−2 S/cm at room temperature and 9.2 × 10−2 S/cm at 70 °C. Methanol permeability of QPES-C membrane was from 5.72 × 10−8 to 1.23 × 10−7 cm2/s over the temperature range 25-70 °C.