Heat may be essential for life, but in some cases – such as protecting the space shuttle or improving the efficiency of a jet engine – materials with low thermal conductivities are needed to prevent passage of too much heat. As reported in the Feb. 13 issue of the journal Science, researchers have created a better thermal insulator by controlling material structure at the nanoscale.
“We explored ways to control thermal properties in materials by introducing structure on nanometer length scales,” said David Cahill, a professor of materials science and engineering and a Willett Faculty Scholar at the University of Illinois at Urbana-Champaign. “By making nanolaminates of dissimilar materials, we found that we could significantly decrease the thermal conductivity because heat cannot be carried efficiently across the material interfaces.”
Cahill, graduate student Ruxandra Costescu and colleagues at the University of Colorado at Boulder first synthesized thin-film nanolaminates composed of alternating layers of tungsten and aluminum oxide using atomic layer deposition and magnetron sputter deposition. Cahill and Costescu then measured the thermal conductivity of the nanolaminates using a technique called time-domain thermoreflectance.
James E. Kloeppel | UIUC
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