The invention is an integrated membrane electrode assembly, method for using the assembly in a proton exchange membrane (PEM) fuel cell, and methods for making the assembly using axially aligned carbon nanotubules. The preferred embodiment of the integrated membrane electrode assembly has at least one proton exchange membrane having a cathode surface and an anode surface, at least one axially aligned carbon nanotubule anode layer disposed on the PEM anode surface, at least one axially aligned carbon nanotubule cathode layer disposed on the PEM cathode surface, and a catalyst disposed along the annulus of the carbon nanotubules of the anode layer and the cathode layer. The assembly transports reaction gases along the aligned axes of the anode and cathode layers in an essentially one-dimensional diffusion pathway for contact with the catalyst thereby improving the mass activity of the assembly.
 This invention was made with Government support under contract no. DE-AC05-00OR22725 to UT-Battelle, LLC, awarded by the United States Department of Energy. The Government has certain rights in the invention.