Abstract: A method is provided for making a hydrophilic carbon fiber construction, such as a fuel cell gas diffusion layer or diffuser/current collector, by electrophoretic deposition of a metal oxide selected from Type I or Type II, where Type I consists of metal oxides having a negative zeta potential and Type II consists of metal oxides having a positive zeta potential. A hydrophilic carbon fiber construction is provided, such as a fuel cell gas diffusion layer or diffuser/current collector, which is coated with a metal oxide and capable of wicking 200 mg of water per 40 mg of the hydrophilic carbon fiber construction.

Abstract: The present invention is a microlayer for use with an electrically conductive porous substrate of a gas diffusion layer. The microlayer includes carbon particles and a polymeric composition of first highly-fluorinated polymers that are non-melt processable and second highly-fluorinated polymers that are melt processable.

Abstract: A method is provided for making a hydrophobic carbon fiber construction, such as a fuel cell gas diffusion layer, by electrophoretic deposition of a highly fluorinated polymer, which may be followed by sintering of the fluoropolymer. A hydrophobic carbon fiber construction is provided, such as a fuel cell gas diffusion layer, which is coated with a monolayer of particles of a highly fluorinated polymer, which may be sintered.

Abstract: The present invention provides a fuel cell gas diffusion layer comprising a hydrophilic surface layer having a thickness of no more than 1 micron, and, thereunder, a hydrophobic second layer comprising a fluoropolymer having a thickness of at least 5 microns. Additionally, the present invention provides a method of making a fuel cell gas diffusion layer comprising the steps of a) providing a carbon fiber construction; b) coating at least the upper surface of the carbon fiber construction with composition which comprises a fluoropolymer; and c) exposing the upper surface to at least one plasma, such as a silane plasma, so as to generate a hydrophilic surface layer having a thickness of no more than 1 micron. The present invention also provides a method additionally comprising the step of partially covering the upper surface with a mask having windows according to a pattern, such that the hydrophilic surface layer is applied according to the pattern.