Methanol diffusion in water swollen ionomer membranes for DMFC applications

The methanol diffusion coefficient was measured for Nafion and two differently cross-linked polyaryl-blend-membranes developed at ICVT. It could be shown that the methanol diffusion coefficient depends on both temperature and membrane water content. For the polyaryl-blend-membranes the methanol diffusion coefficient is approx. 2–2.5 times lower than for Nafion at the same temperature and the same water content. The activation enthalpy for methanol diffusion in Nafion is about 20 kJ mol−1 and decreases with increasing water content.