Nanograss provides effective thermal-transfer surface

Cooling is a constant design challenge. To meet that challenge, researchers at Bell Labs/Lucent are experimenting with a nanostructured surface that reduces viscous drag on cooling fluid. The intention is to use billions of silicon posts to aid in transferring heat from the silicon surface to the liquid coolant. Each post has a water-repellent, Teflonlike surface, so f luids f low without wetting. When researchers apply a small electric current to the posts, the droplets on the surface slick down and wet the surface. This technology allows researchers to study the details of f luid f low and heat transfer across such superhydrophobic surfaces. The nanograss also provides a tenfold increase in the effective surface area of a flat silicon surface, which also facilitates heat transfer.

Lucent Technologies, www.lucent.com