A diffusion media and a process for its fabrication are provided for
addressing issues related to water management in electrochemical cells
and other devices employing the diffusion media. In accordance with one
embodiment of the present invention, a process for fabricating a
diffusion media is provided. A diffusion media substrate is provided
comprising a porous fibrous matrix defining first and second major faces.
The substrate comprises an amount of carbonaceous material sufficient to
render the substrate electrically conductive. A mesoporous layer is
applied along at least a portion of one of the first and second major
faces of the substrate. The mesoporous layer is applied to the substrate
by providing a coating comprising a hydrophobic component, a hydrophilic
component, and a pore forming agent. The substrate is free of fluorinated
polymers outside of regions of the substrate carrying the mesoporous
layer. The pore forming agent is decomposed such that the mesoporous
layer is more porous than the diffusion media substrate.