Since the discovery of carbon nanotubes in 1991, scientists have marveled at the structures' superlative strength and their promising electronic and optical properties. Now it seems that the tubes might also serve as tiny hydropower plants.
New measurements by scientists in India show that a dense bundle of so-called single-wall nanotubes–atom-thick sheets of carbon rolled into cylinders (SN: 1/4/03, p. 14: Carbon nanotubes beam electrons)–develops a voltage difference along its length when immersed in a slow-flowing liquid. Moreover, that electrical potential, which ranges up to 10 millivolts (mV), increases with flow speed.
This newfound trait may lead to nanotubes' use as exquisitely sensitive flow sensors, feedback components in microfluidics devices, or power sources for micromachines, says physicist Ajay K. Sood of the Indian Institute of Science (IIS) in Bangalore. He and his colleagues report their findings in the Feb. 14