Materials Science

An Inside View of Foam

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Science  22 Aug 2008:
Vol. 321, Issue 5892, pp. 1021
DOI: 10.1126/science.321.5892.1021a

From lending texture to a perfect pint, to mediating fluid flow in porous rock, and even capturing space dust in the wake of a comet, foams have a diverse set of mechanical properties, geometrical structures, and applications. Their remarkable strength-to-weight ratio makes them sought after as physical supports, with their large surface area making them ideal scaffolds for catalytic applications. They tend to be rather delicate, however, and the mechanisms whereby the various structures form and then limit the resulting physical properties have not been clear. Barty et al. use coherent x-ray diffraction to provide a detailed three-dimensional image of the internal structure of the highly porous form of tantalum oxide known as aerogel, often described as “frozen smoke.” Combining the exquisite structural information with detailed simulations, they show that the observed blob-and-beam network structure explains why the materials are weaker than expected. Such insight offers a route toward improving the properties through better control of the preparation process. — ISO

Phys. Rev. Lett. 101, 55501 (2008).

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