Polymer electrolytes architectures

Clearly, a fundamental understanding of the key strac-ture/property relationships, particularly membrane morphology and conductivity as a function of polymer electrolyte architecture and water content - both in the bulk hydrated membrane and at the various interfaces within the membrane electrode assembly (MEA), can provide guidance in the synthesis of novel materials or MEA manufacturing techniques that lead to the improvement in the efficiency and/or operating range of PEMFCs. 

Thus, the first task provides a stracture/property relationship between morphology and polymer electrolyte architecture and degree of hydration. The second task aims to determine proton transport as a function of the morphology. Coimecting the two tasks together in sequence then leads to proton transport as a function of polymer electrolyte architecture and degree of hydration. 

K.-B. Min, S. Tanaka, and M. Esashi, Fabrication of novel MEMS-based polymer electrolyte fuel cell architectures with catalytic electrodes supported on porous SiOj, Journal of Micromechanics and Microengineering, 16 (2006) 505-511. 

The membrane in the polymer electrolyte fuel cell (PEFC) is a key component. Not by chance does the type of membrane brand the cell name - it is the most important component determining cell architecture and operation regime. Polymer electrolyte membranes are almost impermeable to gases, which is crucial for gas-feed cells, where hydrogen (or methanol) oxidation and oxygen reduction must take place at two separated electrodes. However, water can diffuse through the membrane and so can methanol. Parasitic transport of methanol (methanol crossover) severely impedes the performance of the direct methanol fuel cell (DMFC). 

Min K, Tanaka S, Esashi M (2003) Silicon-based micro-poljnner electrolyte fuel cells. In IEEE intemational conference on micro electro mechanical systems, Kyoto Min K, Tanaka S, Esashi M (2006) Fabrication of novel MEMS-based polymer electrolyte fuel cell architectures with catalytic electrodes supported on porous Si02- J Micromech Microeng 16 505-511 Miu M, Danila M, Ignat T, Craciunoiu F, Kleps I, Simion M, Bragam A, Dinescu A (2009) Metallic-semiconductor nanosystem assembly for miniaturized fuel cell applications. Superlatt Microstmct 46 291-296... 

FIGURE 7.6 Synthesis scheme of a highly branched polyphosphazene. (Reprinted with permission from Allcock, H.R., Sunderland, N.J., Ravikiran, R., and Nelson, J.M., Polyphosphazenes with novel architectures Influence on physical properties and behavior as solid polymer electrolytes. Macromolecules, 31, 8026. Copyright 1998 American Chemical Society.)... 

Then we address the dynamics of diblock copolymer melts. There we discuss the single chain dynamics, the collective dynamics as well as the dynamics of the interfaces in microphase separated systems. The next degree of complication is reached when we discuss the dynamic of gels (Chap. 6.3) and that of polymer aggregates like micelles or polymers with complex architecture such as stars and dendrimers. Chapter 6.5 addresses the first measurements on a rubbery electrolyte. Some new results on polymer solutions are discussed in Chap. 6.6 with particular emphasis on theta solvents and hydrodynamic screening. Chapter 6.7 finally addresses experiments that have been performed on biological macromolecules. 

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