Abstract
We report the preparation of a new class of organic/inorganic hybrid aerogels from aryl-bridged polysilsesquioxanes [1]. l,4-Bis(triethoxysilyl)benzene and 4,4'-bis(triethoxysilyl)-biphenyl were sol-gel processed to form phenyl- and biphenyl-bridged polysilsesquioxane gels (Figure 1, structures 1 and 2, respectively). The gels were then dried using supercritical carbon dioxide extraction. It was discovered that aryl-bridged polysilsesquioxane aerogels are indeed formed, but with a pronounced influence on surface area from the reaction conditions used in preparing the initial gels. Specifically, high surface aerogels ( up to 1750 m2/g) are obtained from gels prepared with either acid or base catalysts. With reduced concentrations of base catalyst, however, supercritical processing afforded phenyl-bridged xerogel-like materials, The materials were characterized by nitrogen sorption surface analysis, and by transmission electron microscopy.
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Acknowledgements
We would like to thank Robert Dosch for the use of his gas sorption porosimeter, and Linda McLaughlin for her invaluable assistance in running the surface area analyses. We must also gratefully acknowledge the expertise of Thomas Headley, who provided us with transmission electron micrographs. This work was supported by the United States Department of Energy under contract # DE-AC04-76DP00789.
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Loy, D.A., Shea, K.J. & Russick, E.M. Preparation of Aryl-Bridged Polysilsesquioxane Aerogels. MRS Online Proceedings Library 271, 699–704 (1992). https://doi.org/10.1557/PROC-271-699
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DOI: https://doi.org/10.1557/PROC-271-699