F141 Local self-diffusion measurement of water molecular in polymer electrolyte membrane using a planar surface coil

Abstract

The local NMR sensor consisting of the planar surface coil of 0.8mm and 2.0mm outside diameter and a permanent magnet was developed to measure local self-diffusion coefficient of water molecular in a polymer electrolyte membrane (PEM) for fuel cell. Using the pulse-field-gradient spin echo method as a pulse sequence in the NMR system, the relationship between self-diffusion coefficient of water molecular in the PEM at 55, 65 and 75℃ and vapor concentration in the N_2 carrier gas was obtained. The accuracy of self-diffusion coefficient of water molecular in the PEM with three different water contents measured by the planar surface coils was evaluated by the comparison with that measured by the conventional solenoid coil.