A153 Study on Measurement Technique for Mass Diffusion Coefficient in Polymer Electrolyte Membrane for Fuel Cell by Soret Forced Rayleigh Scattering Method : Development of Experimental Apparatus Using CO_2 Laser

Abstract

Methanol crossover to the cathode not only lowers fuel utilization efficiency but also adversely affects the oxygen cathode in direct methanol fuel cell (DMFC). Because methanol is transported by diffusion and convection, diffusion coefficient of methanol aqueous solution in membranes is important parameter for the performance of DMFC. In the present study, we have developed Soret Forced Rayleigh Scattering Method (S-FRSM) using CO_2 laser to measure diffusion coefficient of methanol solution in polymer membrane. To control the pulse time and timing of the laser irradiation, two acoust-optic modulators (AOMs) were adopted in the apparatus newly developed.