By 'drawing' on paper with a pencil-like tool containing carbon nanotubes, researchers have created a prototype gas sensor.
Researchers developing sensors that can detect hazardous gases have struggled to find a method that is both low-cost and high-performance. Timothy Swager and his colleagues at the Massachusetts Institute of Technology in Cambridge suggest an approach that may meet both requirements. The researchers have created an electrical circuit by abrading a packed pellet of single-walled carbon nanotubes onto paper, as if drawing with a pencil. When the deposited carbon nanotube layers are exposed to ammonia, a hazardous gas, it triggers measurable changes in the nanotubes' electrical conductivity.
The prototype gives results with similar sensitivity and reproducibility to those of carbon-nanotube sensors deposited using solutions, the researchers say, but their device is less expensive and easier to fabricate and handle.
Angewandte Chemie Int. Ed. http://dx.doi.org/10.1002/anie.201206069 (2012)