Polymer electrolyte membrane polymeric membranes

Schematic depiction of the structural evolution of polymer electrolyte membranes. The primary chemical structure of the Nafion-type ionomer on the left with hydrophobic backbone, side chains, and acid head groups evolves into polymeric aggregates with complex interfacial structure (middle). Randomly interconnected phases of these aggregates and water-filled voids between them form the heterogeneous membrane morphology at the macroscopic scale (right).

The development of transparent polymer electrolyte membrane from the bi-continuous-microemulsion polymerization of 4-vinylbenzene sulfonic acid Hthium salt (VBSIi), acrylonitrile and a polymerizable non-ionic surfactant, co-methoxypoly(ethylene oxide)4o-undecyl-a-methacrylate (Ci-PEO-Cn-MA-40) was reported in 1999 [94,95]. The ionic conductivities of the polymer electro-... 

Many different kinds of fuel cells are presently known, most of them suitable for high-temperature applications— for details see Ref. [101]. The polymeric proton-conducting membranes (polymer electrolyte membranes PEM) are however suitable for low temperamre operations (<100°C) and have the advantage of low weight. 

The proton exchange membrane - also known as polymer electrolyte membrane (PEM) - fuel cell uses a polymeric electrolyte. The protonconducting polymer forms the heart of each cell electrodes, usually made of porous carbon with catalytic platinum incorporated into them, are bonded to either side of the electrolyte to form a one-piece membrane-electrode assembly (MEA). The following are some key advantages that make PEMs such a promising technology for the automotive market ... 

The temperature of operation of polymer electrolyte membrane fuel cells tends to get higher, because certain advantages are faced, such as improved tolerance of carbon monoxide, the improved ease of water and heat management, and increased energy efficiency. However, several commonly used polymeric membranes cannot withstand the high temperatures. Therefore, there is a need to look for alternative materials. 

Polymeric functional materials are of central importance for the polymer electrolyte membrane fuel cell (PEMFC) and DMFC technologies in particular. In addition to the expected cost reduction due to low-cost mass productimi, for example of polymeric bipolar plates (see Sect. 2.1), the polymeric membranes are irreplaceable in the PFMFC and DMFC technologies. 

In the Proton-Exchange Membrane Fuel Cell (or Polymer-Electrolyte Membrane Fuel Cell) the electrolyte consists of an acidic polymeric membrane that conducts protons but repels electrons, which have to travel through the outer circuit providing the electric work. A common electrolyte material is Nafion from DuPont , which consists of a fluoro-carbon... 

In general, different routes for preparation of polymer electrolyte membrane based on IL have been used and classified into three categories (I) doping of polymers with IL by (a) the immersion of an already formed polymer membrane into a IL solution and (b) by mixing both IL and polymer solution for a certain period of time followed by evaporation of solvent, membranes prepared by this route have been also labeled as polymer gel-type (II) in situ polymerization or cross-linking of monomers in IL by the reactions between IL and polymeric monomers to form IL/polymer membranes ... 

This process is usually performed for manufacturing of single MEAs discontinuous. Via the GDE process, the pre-manufactured catalyst-loaded gas diffusion electrode loaded with catalyst is pressed together with a polymer electrolyte membrane to form an MEA. The doping procedure can take place on the membrane or the electrode. This process is widely used due to the fact that the polymeric membrane is not stressed as much as in the other manufacturing techniques. Less beneficial, here the production and assembling costs have to be mentioned. Every component has to get manufactured, cut, and assembled separately. But this lead to excellent possibilities to exclude material with low quality early. 

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