Tiny fibers used to find explosives

CARBONDALE, ILL. -- Nanofibers are about 1/250,000th of an inch across, but they could have a huge impact on such diverse areas as national security, factory safety and aerospace construction.

Dr. Ling Zang, assistant professor of chemistry and biochemistry at Southern Illinois University at Carbondale, recently received a $592,000, five-year CAREER grant from the National Science Foundation to continue his research with nanofibers.

Zang said the CAREER grant is a follow-up to a one-year grant for $100,000 he received last year.

"We got exciting results in our first year of research," Zang said. "I think our progress convinced the NSF that we deserved further funding."

Zang creates organic fibers that can, among other things, detect a minuscule amount of explosive material in the Nanoscale Exploration and Single Molecule Imaging lab at SIU.

The fibers' natural fluorescence is "quenched" by TNT molecules, according to Zang.

"We see about a 50 percent decrease in the fluorescent properties of our nanofibers when TNT is present, even in very small amounts," Zang said.

The fibers are more sensitive than current detection systems and reduce false positive tests, according to Zang.

Dr. Hao Li, assistant professor of material science at University of Missouri-Columbia, is also studying nanofibers on a NSF grant.

Li's research focuses on creating superstrong nanocomposite fibers for use in aerospace construction. Li said the fibers are more than 100 times stronger than stainless steel.

"There are a lot of fascinating research opportunities in nanofibers," Li said. "For instance, the elements of the human body are nano-sized. We are working on a sensor using nanofibers that can detect viruses and traces of DNA."

Li shares his NSF grants, which total more than $1 million, with several other faculty members.

"There are so many opportunities for collaboration with other disciplines, medicine, engineering," Li said. "It's very cutting edge."

Zang said his lab's NSF grant also will provide for research into nanofibers that have a variety of applications.

"We're going to move beyond sensory nanotechnology in the next five years," Zang said. "We are working on fibers that could possibly convert solar energy into electrical current and optoelectronic devices that can monitor barely-detectable electric currents."

Some of Zang's fibers also are being constructed to sense poisonous gases.

Hydrazine, a component of rocket fuel, is one of the gases the fibers can detect.

"Humans can only tolerate a certain, small amount of hydrazine," Zang said. "We need sensors for the factories where it is produced."

According to Zang's research, the national budget for nanotechnology has more than quintupled in the past six years, and the number of published papers on nanotechnology has more than tripled.

Zang has been invited to present papers on his nanofiber research to scientific conferences more than 20 times in his career. But he is quick to share credit for his achievements with his team of researchers.

"I was very excited about the grant because it is physical proof of our progress," Zang said. "I have a dynamic team of talented students working for me. This award is for the whole team."

pwylie@semissourian.com

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