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.