Cited research: Nano Lett. doi:10.1021/nl100235n (2010)

Thin sheets of carbon nanotubes can generate sound underwater 100 times more efficiently than predicted theoretically, say researchers at the University of Texas at Dallas.

Such sheets can generate sound in air when an electric current is applied, by heating up and creating pressure waves in the surrounding air. Ali Aliev and his colleagues found that when their nanotube-based device is placed in water (pictured), a thin layer of air surrounds the hydrophobic sheets, providing a barrier against the water. This enhances the acoustic vibration and also prevents the water from degrading the nanotubes. The authors suggest that the sheets could be fashioned into flexible and lightweight loudspeaker 'skins' for vehicles both on land and underwater. E.H.

Credit: A. E. ALIEV/NANOTECH INST./UNIV. TEXAS AT DALLAS