Composite ionomer membranes

Inorganic/Organic (Fluorinated) Composite Ionomer Membranes... 

Composites between polypyrrole and a variety of porous materials such as paper, cloth or wood have been made. Often the respective material was impregnated with an oxidant such as FeCls and subsequently contacted with pyrrole vapor or solution. For example, polypyrrole (and polyaniline) have been made in Nafion perfluorosulfonated ionomer membranes by treatment with aqueous ferric chloride and the monomers. ... 

M. Doyle, S.K. Choi and G. Proulx, High-temperature proton conducting membranes based on perfluorinated ionomer membrane-ionic liquid composites, J. Electrochem. Soc., 2000, 147, 34-37. 

P. Millet, R. Durand, E. Dartyge, G. Tourillon and A. Fontaine, Preparation of metallic Platinum into Nafion ionomer membranes. 1. Experimental results, J. Electrochem. Soc., 1993, 140, 1373 P. Millet, F. Andolfatto and R. Durand, Preparation of solid polymer electrolyte composites investigation of the precipitation process, J. Appl. Electrochem., 1995, 25, 227. 

The use of low-cost basic polymers instead of Nation is an interesting alternative [19,20].The development of new polymers for ionomer membranes including perfluorinated ionomers, partially fluorinated ionomers, nonfluorinated ionomers, high-molecular/low-molecular composite membranes as well as novel polymer modification processes and novel membrane materials is summarised in [21]. 

Neutralizing the acid groups in the dispersion leads to formation of an ionomer membrane in the latex film [63]. As shown in Figure 14.24, this ionomer phase has a profound effect on slowing down the interdifiusion and on broadening the distribution of diffusion rates. In spite of the complexity of the system, there is a quite simple explanation for these effects. The shell polymer has a higher Tg than that of the core. The Tg of the shell phase depends upon composition the... 

Several reviews on membranes for DMFC fuel cells have been published in the last decade [1-9], starting with that by Kreuer [1], discussing the differences between Nafion and sulfonated polyether ketone membranes. According to Fig. 6.1, reviews published till 2006 [1 ] cover only one third of the ionomeric membranes currently developed for DAFC. More recent reviews deal with polyimide ionomer membranes [5], composite membranes for high temperature DMFC [6], non-perfluorated sulfonic acid membranes [7], modified Nafion membranes [8], and hybrid membranes [9-11]. 

The simplest way to improve the proton conductivity of ionomer membranes is to increase lEC, either by using monomers with short side chains or by increasing copolymer composition of sulfonic acid-containing units. The former approach... 

The group of GKSS Research Center Germany extensively researched the effect of a variety of inorganic nanoparticles on the properties of aromatic ionomer membranes [86-93]. Composite membranes were prepared from silicates and sulfonated poly(ether ketone)s or sulfonated poly(ether ether ketone)s. For DMFC applications, the composite membranes showed promising properties with lower methanol and water permeability and comparable (or higher) proton conductivity compared to the parent polymer membranes. The flux of water and methanol decreased with the increase in content of silicates. 

Developing ionomer membranes that are more thermostable is the most essential answer to improving their thermal durabUity. Endoh and his coworkers at Asahi Glass (Endoh, 2006) reported that their newly developed MEA, composed of a new perfluorinated polymer composite, could be operated for more than 4000 hours at 120°C and 50% RH compared to a conventional MEA, their new MEA could reduce the degradation rate to 1/100-1/1000. However, the detailed chemical structure of their new membrane has so far not been disclosed. 

Use of sulfonated polymers as the proton-conductive component in the fuel cell membranes at T < 100°C Use of nonfluorinated ionomers physical and/or chemical cross-linking of the fuel cell membranes Use of nonfluorinated ionomers physical and/or chemical cross-linking of the fuel cell membranes Development of organic-inorganic composite membranes, based on our cross-linked ionomer membrane systems, in which the inorganic membrane component serves as water storage or even contributes to H -conduction Use of commercially available polymers for chemical modification and membrane formation, which avoids expensive development of novel polymers... 

---