An electrochemical fuel cell comprises an anode electrocatalyst layer, a
cathode electrocatalyst layer, a polymer electrolyte membrane interposed
between the anode and cathode electrocatalyst layers, an anode flow field
plate, a cathode flow field plate, an anode fluid distribution layer
interposed between the anode flow field plate and the anode
electrocatalyst layer, and a cathode fluid distribution layer interposed
between the cathode flow field plate and the cathode electrocatalyst
layer, wherein at least one of the anode and cathode fluid distribution
layers decreases in permeability from an inlet to an outlet of the
electrochemical fuel cell. Methods for making a substantially fluid
impermeable sheet material having a non-uniform pattern of perforations
are also provided.