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In this research a series of pore‐filling electrolyte membranes were prepared, based on a sulfonated and hydrogenated styrene/butadiene block copolymer (SHSBS) and plasma‐treated microporous polyethylene (PE) membranes. The pore‐filling electrolyte membranes were characterized by means of scanning electronic microscopy (SEM), infrared spectroscopy (FTIR‐ATR), and dynamic mechanical analysis (DMA). In addition, the water uptake and methanol/water uptake capacities of these membranes were determined using several methanol in water solutions, as well as the permeability coefficients, for both water and methanol, using a 2 M methanol in water solution and pure methanol. Finally, electrical behavior was recorded by means of electrochemical impedance spectroscopy (EIS) and the four probe technique (FPT). The SEM images recorded show good coating of the pore‐filling electrolyte membranes on the plasma‐treated PE matrices, and DMA shows the proper relaxations of the two components: PE and SHSBS. Furthermore, the methanol/water absorption capacity was observed to diminish with plasma treatment of the matrix. Methanol permeability of the pore‐filling electrolyte membranes is notably lower than that of the Nafion® membrane, ion conductivity moving in the order of 10−2 S cm−1. Both of these characteristics qualify the experimental membranes as candidates to be applied as proton exchangers in fuel cells (FCs). © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1684–1695, 2008

The gas diffusion layer (GDL) is one of the most important parts of a proton exchange membrane fuel cell, that plays a key role transporting the current to the collector plates, distributing the reactant gases to the catalyst surface, and evacuating heat and water that is generated during the redox reactions inside the fuel cell. Speaking in terms of production cost, the GDL represents up to 45% of the total cost of the membrane electrode assembling (MEA). However, and despite its crucial role in a fuel cell, until recent years, the GDLs have not been studied with the same intensity as other MEA components, such as the catalyst or the proton exchange membrane. In this work, we present the production process, at laboratory scale, of a low cost GDL, using a non-woven paper-making process. A relevant aspect of this GDL is that up to 40% of their composition is natural cotton, despite which they present good electrical and thermal conductivity, high porosity, good pore morphology, high hydrophobicity as well as gas permeability. Furthermore, when the GDL with its optimum cotton content was tested in a single open cathode fuel cell, a good performance was obtained, which makes this GDL a promising candidate for its use in fuel cells.

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