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In situ implantation of PolyPOSS blocks in Nafion® matrix to promote its performance in direct methanol fuel cell

Department of Chemical and Biomolecular Engineering, National University of Singapore, BLK E5 02-02, 4 Engineering Drive 4, Singapore 117576, Singapore; Institute of Materials Research & Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602, Singapore
Journal of Membrane Science 01/2008; DOI: 10.1016/j.memsci.2008.04.013

ABSTRACT Fabrication of recast Nafion®-117 membrane using the dipolar aprotonic solvent will normally lead to a random matrix. On the contrary, when a designed amount of vinyl-pendant octasiloxane (Q8M8V) cubic molecules was included into the Nafion® matrix during the recasting process and then subjected to polymerization, a nonrandom matrix was obtained. This paper provides an insight into the matrix-formatting role of rigid poly(Q8M8V) blocks, generated in situ in Nafion® matrix, according to thermal analyses (thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and Differential Scanning Calorimetry (DSC)) and electron microscopic images of the resulting composite matrix. The P(Q8M8V) played a role in restricting random extensions of proton-conducting channels (PCCs) and promoted ordered assembling of Nafion® molecules. As a result, compared with the recast pristine Nafion® membrane, the composite membranes containing P(Q8M8V) of 5–15 wt.% manifested obvious improvement on both repression of methanol permeability and promotion of power density output of the single direct methanol fuel cell (DMFC).

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