Inspiration for the current study is derived from the fact that despite significant studies on polybenzimidazole (PBI) nanocomposite based proton exchange membrane (PEM) for fuel cells, the importance of understanding the nanocomposite interface has been inadequately addressed in literature till date. Since the interphase structure is closely related to the surface functionalization of the nanoparticles (NPs), there is a need to explore the surface chemistry in order to develop materials with desired properties. In my presentation, I would like to share our findings on the effect of aliphatic chain length of the surface modifier of silica NPs on important properties of PBI nanocomposite membranes for use as PEM and to underline the quantitative links between dispersion pattern of NPs in the polymer matrix with proton conductivity and different kinds of stability. Silica NPs decorated with long chain amine silane coupling agent (LAMS) was used to induce the compatibility with oxy-polybenzimidazole (OPBI) matrix. Structure and morphology analysis of nanocomposites by WAXD and TEM, respectively, showed the formation of self-assembled networks of the modified NPs in the (OPBI/LAMS) matrix, whereas a completely dispersed structure was observed for the unmodified NPs (UMS) in the (OPBI/UMS) matrix. The self-assembly of LAMS NPs helped in increasing proton conductivity by creating more proton hopping sites. Large mechanical reinforcements were obtained with OPBI/LAMS membranes.The presence of LAMS’ assembly safe-guards the polymer chains from thermal and oxidative degradation thus enhancing the membranes’ stability and durability in fuel cell operating conditions. Water uptake and dimensional stability studies of the membranes showed promising results. Reference 1.Schadler,L. et al Mater. Res. Soc.Bull. 2007,32,335.

Effect of interfacial modification on the morphology and properties of polybenzimidazole/silica nanocomposite proton exchange membrane for use in fuel cells

249th National Meeting (2015)

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