Rensselaer Polytechnic Institute researchers determined that when such a block is compressed, individual carbon nanotubes start to buckle. That decreases the block's electrical resistance, which can be measured to determine precisely how much pressure is being applied.
The scientists found no matter how many times or how hard they squeezed the block, it exhibited a constant, linear relationship between how much force was applied and electrical resistance.
"Because of the linear relationship between load and stress, it can be a very good pressure sensor," said Subbalakshmi Sreekala, a postdoctoral researcher at Rensselaer and author of the study.
Sreekala said a sensor incorporating the carbon nanotube block would be able to detect very slight weight changes, making it useful in a wide range of applications, such as checking a car's tire pressure or as a microelectromechanical pressure sensor used in semiconductor manufacturing.
The research that also included Professors Pulickel Ajayan, Omkaram Nalamasu and Daniel Gall, as well as Lijie Ci, Ashavani Kumar and Sai Kesapragada, appeared in a recent issue of Applied Physics Letters.