Patent ID: 7303835

Claim:
A porous diffusion media comprising a porous matrix carrying a distribution of water transfer particles, wherein: said diffusion media defines a major planar dimension and first and second major faces substantially parallel to said major planar dimension of said diffusion media; said distribution of water transfer particles defines a plurality of high particle density regions characterized by a relatively high density of said water transfer particles and a plurality of low particle density regions characterized by a relatively low density of said water transfer particles; said relatively high and relatively low particle density regions alternate across said major planar dimension of said porous diffusion media; respective properties of said relatively high and relatively low particle density regions vary across a cross section of said porous diffusion media between said first and second major faces of said diffusion media such that said first major face is collectively more hydrophilic than said second major face and said second major face is collectively more hydrophobic than said first major face, wherein the first major face and the second major face each comprise hydrophilic and hydrophobic portions; and said porous diffusion media further comprises a layer of hydrophobic material disposed along one of said first or second major faces of said diffusion media.