New material allows for better bomb-sniffing technology

Engineers have developed a new type of carbon nanotube material for the next generation of handheld sensors that will be quicker and better at sniffing out explosives, deadly gases and illegal drugs.
A carbon nanotube is a cylindrical material that is a hexagonal or six-sided array of carbon atoms rolled up into a tube.
Carbon nanotubes are known for their strength and high electrical conductivity and are used in products from baseball bats and other sports equipment to lithium-ion batteries and touchscreen computer displays.
The new kind of nanotubes, developed by University of Utah scientists, also could lead to flexible solar panels that can be rolled up and stored or even "painted" on clothing such as a jacket.

Vaporsens, a university spin-off company, plans to use the carbon nanotube material to build a prototype handheld sensor by year's end and produce the first commercial scanners early next year, said co-founder Ling Zang, a professor of materials science and engineering and senior author of the study.
Zang and his team found a way to break up bundles of the carbon nanotubes with a polymer and then deposit a microscopic amount on electrodes in a prototype handheld scanner that can detect toxic gases such as sarin or chlorine, or explosives such as TNT.

When the sensor detects molecules from an explosive, deadly gas or drugs such as methamphetamine, they alter the electrical current through the nanotube materials, signalling the presence of any of those substances, Zang said.

"You can apply voltage between the electrodes and monitor the current through the nanotube," said Zang.
""If you have explosives or toxic chemicals caught by the nanotube, you will see an increase or decrease in the current," Zang added.
By modifying the surface of the nanotubes with a polymer, the material can be tuned to detect any of more than a dozen explosives, including homemade bombs, and about two-dozen different toxic gases, said Zang.
The technology also can be applied to existing detectors or airport scanners used to sense explosives or chemical threats.
The study is published in the journal Advanced Materials.