Durability of proton exchange membrane fuel cells (PEMFCs) is likely to be significantly influenced by the properties of the gas diffusion layer material. An optimum humidification level and water distribution within the gas diffusion media are required to lower the ohmic resistance and prevent the appearance of hot spots in the catalyst coated membrane. In the same time such optimum humidification level and distribution must minimize reactant mass transport losses in the gas diffusion layer. For proper cell design and water management the transport properties of the gas diffusion media must be evaluated. In this paper we describe techniques for evaluation the through-plane and in-plane viscous and inertial permeability, the internal contact angle to water and the surface energy of macro and micro-porous substrates of gas diffusion layer materials.
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