Liquid water transport between graphite paper and a solid surface

We studied the interaction of a water droplet with a solid wall on a hydrophobic gas diffusion layer (GDL). Of particular interest is the stability of the droplet as a function of plate wetting properties and the potential for liquid entrapment in the GDL/land contact area. Such transport is of relevance to breakthrough dynamics and convective liquid droplet transport in polymer electrolyte membrane (PEM) fuel cell cathode gas channels. While a variety of complex coupled transport phenomena are present in the PEM fuel cell gas channel. we utilize a very simplified experimental model of the system where a droplet originally placed on a hydrophobic GDL is translated quasistatically across the GDL surface by a solid surface. Transport and entrapment are imaged using fluorescence microscopy. This work provides new insights into droplet behaviour at the GDL/land interface in a PEM fuel cell and suggests that hydrophobic land areas are preferable for mitigating the accumulation of liquid water under the land area of the gas flow channels. (C) 2008 Elsevier B.V. All rights reserved.