Patent ID: 7250189

Claim:
A method for making a hydrophilic wicking fuel cell diffusion medium comprising: exposing a carbon fiber substrate to a solution comprising a monomer and an electrolyte, wherein the concentration of monomer is from about 0.5 M to about 1.5 M and the concentration of electrolyte is from about 0.01 M to about 1.5 M; and electropolymerizing the monomer to form an electroconductive polymer on the carbon fiber substrate, wherein electropolymerizing includes: providing the carbon fiber substrate as the anode of an electrochemical circuit including a counter-electrode; applying a positive potential to the anode using a pulse voltage, the pulse voltage including a square wave function having a frequency from about 0.1 Hz to about 0.001 Hz, wherein the anode is at a voltage above the oxidation potential of the monomer; thereby oxidizing the monomer to form the electroconductive polymer on the carbon fiber substrate surface.