Nanotube speakers outperform sonar equipment

Scientists at the NanoTech Institute in Dallas showed that nanotube speakers worked just as well in water as they did in air and could also cancel out unwanted noise.

The University of Texas at Dallas research team, led by Dr Ali Aliev, found the nanotubes were more efficient at producing the low-frequency sound waves used to scan the ocean than the existing sonar equipment.

The nanotubes’ success in producing sound in the ocean was due to the fact they repel water slightly and form a layer of air along their perimeter.

Instead of producing sound vibrations like traditional speakers, nanotubes heat and cool very quickly when alternating current is passed through them, producing a pressure wave that can be detected as sound.

Water needs more energy than air to change its temperature and doesn’t expand as much when heated. But the layer of air around the nanotubes meant they could still produce this ‘thermoacoustic’ sound in the ocean.