Sulfonic and Phosphonic Acid and Bifunctional Organic–Inorganic Hybrid Membranes and Their Proton Conduction Properties |
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| Authors: | Dr Ozlem Sel Dr Thierry Azais Dr Manuel Maréchal Dr Gérard Gébel Prof Christel Laberty‐Robert Prof Clément Sanchez |
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| Institution: | 1. LCMCP‐CNRS‐UMR‐7574‐Collège de France, Bat. C‐D, 11, place Marcelin Berthelot, 75231 Paris (France), Fax: (+33)?144‐271‐504;2. Peter A. Rock Thermochemistry Laboratory and NEAT ORU, University of California at Davis, Davis, California, 95616 (USA);3. UJF, CNRS, CEA, CEA Grenoble, UMR 5819, Structure & Propriétés Architectures Moléculaires, INAC,SPrAM, F‐38054 Grenoble 9 (France) |
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| Abstract: | Hybrid organic–inorganic approaches are used for the synthesis of bifunctional proton exchange membrane fuel cell (PEMFC) membranes owing to their ability to combine the properties of a functionalized inorganic network and an organic thermostable polymer. We report the synthesis of both sulfonic and phosphonic acid functionalized mesostructured silica networks into a poly(vinylidenefluoride‐co‐hexafluoropropylene) (poly(VDF‐co‐HFP) copolymer. These membranes, containing different amounts of phosphonic acid and sulfonic acid groups, have been characterized using FTIR and NMR spectroscopy, SA‐XRD, SAXS, and electrochemical techniques. The proton conductivity of the bifunctional hybrid membranes depends strongly on hydration, increasing by two orders of magnitude over the relative humidity (RH) range of 20 to 100 %, up to a maximum of 0.031 S cm?1 at 60 °C and 100 % RH. This value is interesting as only half of the membrane conducts protons. This approach allows the synthesis of a porous SiO2 network with two different functions, having ? SO3H and ? PO3H2 embedded in a thermostable polymer matrix. |
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| Keywords: | conducting materials fuel cells membranes mesoporous materials silica |
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