Technique for characterization of the wettability properties of gas diffusion media for proton exchange membrane fuel cells

In this paper, a measurement technique based on the capillary penetration method is presented for use in estimating the wettability properties of gas diffusion media (GDM), a component for proton exchange membrane fuel cells (PEMFCs). The present method solves several critical issues, including the formation of an external meniscus and the evaporation of imbibed solvent, both of which greatly affect the apparent rate of solvent imbibition. Solvent evaporation is prevented by inserting a GDM sample between two thin stainless steel plates to form a tri-layer structure having non-porous evaporation covers on each side of the porous GDM sample. The presence of stainless steel plates in contact with the GDM sample was demonstrated to have a negligible impact on the evaluation of the Washburn material constant.

In this paper we present a measurement technique based on the capillary penetration method for the estimation of wettability properties of gas diffusion media for proton exchange membrane fuel cells.Figure optionsDownload high-quality image (195 K)Download as PowerPoint slideResearch highlights
► Measuring internal contact angle of solvents in GDMs requires estimating the Washburn constant.
► The external meniscus and the evaporation of imbibed solvent affect the rate of solvent imbibition.
► Placing the GDM between stainless steel plates is an effective way to prevent solvent evaporation.
► The stainless steel plates have negligible impact on the evaluation of the Washburn constant.