(220d) Interfacial Transport Resistances and Coupled Transport
AIChE Annual Meeting
2017
2017 Annual Meeting
Separations Division
Fuel Cell Membranes
Monday, October 30, 2017 - 4:09pm to 4:27pm
These functional constraints have been confirmed by detailed studies of water and proton fluxes across Nafion based membrane electrode assemblies. For small electric potential differences (ÎΦ) the water and proton fluxes are correlated; both increase linearly with applied potential. The electro-osmotic drag coefficient is constant, functionally independent of the applied electrical potential, water activity and temperature. For larger applied electric potential differences the water and proton fluxes are no linearly dependent on applied potential; the electro-osmotic drag coefficient increases with increasing applied electrical potential and increasing water activity. The transition between intramembrane transport limited flux and interfacial transport limited flux corresponds to the limits of applicability of the standard Onsager reciprocal relationships for coupled transport.Â