NOVELTY - Structure of a proton exchange membranes (PEM) with different molecular permeabilities comprises a nano-scale cationic exchange group aggregate structure uniformly distributed in a polymer substrate phase. The rate of reverse permeability of water molecules on cathode back to anode in the proton exchange membrane structure is greater than the permeability of methanol molecules from the anode to the cathode.    USE - In direct methanol fuel cell.    ADVANTAGE - The PEM membrane changes the phase separated structures of hydrophilic/hydrophobic phases in the conventional PEM membranes to become the design in the phase separated structures of crystalline and amorphous phases to reduce the swelling of materials in fuels for achieving the requirement of low methanol permeation. In addition, it increases the ion exchange capacity by polymer grafting reactions. By controlling the concentrations of reaction materials, it prevents forming bulky ion aggregate clusters. The ion aggregates are uniformly distributed on the surface of the materials, so the materials would present a greater water uptake but lower methanol permeation in the performance of the materials. The water molecules in the proton exchange membranes can have higher reverse permeable rate than in Nafion (RTM; perfluorinated polymer). Therefore the permeable rate of water is higher than the one of methanol molecules in order to achieve the function of recovering water on the cathode. The crystalline structure of the materials inhibits material swelling in methanol and ion clusters of the materials are limited in nano-scale space due to the control of crystalline polymers, which achieves the low methanol permeability and high water permeability at the same time. By controlling the polymer grafting reaction, the PEM membrane increases the numbers of ion exchange capacity values, but the space of ionic cluster structures of PEM is limited to the tiny nano-scale. The proton exchange membrane can fit the requirements of the proton conductivity and low methanol permeation, especially the reverse permeability of water molecules, which is greater than the permeability of methanol molecules. The cost of the polymer materials selected is inexpensive and it is easier to produce than the conventional fully fluorinated polymeric materials, which would be more economical.    DETAILED DESCRIPTION - The methanol permeability is less than 1x10-6 cm2/sec and proton conductivity is larger than 1x10-2 S/cm in methanol solutions. The ratio of the reverse permeability of water to the methanol permeability is greater than one. The organic polymer membrane substrate is added with fluoro resin and non-fluoro resin to form a composite membrane. An INDEPENDENT CLAIM is included for a method of making the structure of the proton exchange membranes.