Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1484348 | Journal of Non-Crystalline Solids | 2008 | 7 Pages |
Abstract
We discuss two methods by which high porosity silica aerogels can be engineered to exhibit global anisotropy. First, anisotropy can be introduced with axial strain (i.e. axial compression). In addition, intrinsic anisotropy can result during growth and drying stages and, suitably controlled, it can be correlated with preferential radial shrinkage in cylindrical samples. We have performed small angle X-ray scattering (SAXS) to characterize these two types of anisotropy. We show that global anisotropy originating from either strain or shrinkage leads to optical birefringence and that optical cross-polarization studies are a useful characterization of the uniformity of the imposed global anisotropy.
Keywords
Related Topics
Physical Sciences and Engineering
Materials Science
Ceramics and Composites
Authors
J. Pollanen, K.R. Shirer, S. Blinstein, J.P. Davis, H. Choi, T.M. Lippman, W.P. Halperin, L.B. Lurio,