The sensitive side of carbon nanotubes: Creating powerful pressu...( Troy N.Y. Blocks of carbon nanotube...)

Troy, N.Y. Blocks of carbon nanotubes can be used to create effective and powerful pressure sensors, according to a new study by researchers at Rensselaer Polytechnic Institute.

Taking advantage of the materials unique electrical and mechanical properties, researchers repeatedly squeezed a 3-millimeter nanotube block and discovered it was highly suitable for potential applications as a pressure sensor. 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.

A sensor incorporating the carbon nanotube block would be able to detect very slight weight changes and would be beneficial in any number of practical and industrial applications, Sreekala said. Two potential applications are a pressure gauge to check the air pressure of automobile tires, and a microelectromechanical pressure sensor that could be used in semiconductor manufacturing equipment.

Despite extensive research over the past decade into the mechanical properties of carbon nanotube structures, this study is the first to explore and document the materials strain-resistance relationship. The paper, titled Effects of compressive strains on electrical conductivities of a macroscale carbon nanotube block, was published in a recent issue of Applied Physics Letters.

Over the course of the experiment, the researchers placed the carbon nanotube block in a vice-like machine and applied different levels of stress. They took note of the stress applied and measured the corresponding strain put on the nanotube block. As it was being squeezed, the researchers also sent an electrical charge through the block and measured its resistance, or how easily
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