Juan Duque conquered many obstacles to find success at Rice

No rest for this creative mind
Juan Duque conquered many obstacles to find success at Rice

BY MIKE WILLIAMS
Rice News staff

Sometimes even a guy like Juan Duque has to take a break.

”I have this pillow here,” he said, pulling a clump of air-filled packing material off a shelf in his tiny office in Abercrombie Lab. ”I use it if I need to close my eyes for a few minutes.”

	Juan Duque, a Rice doctoral student in the Chemical and Biomolecular Engineering Department, has published his third nanoscience paper, and already it's old news. He's on to a fourth and fifth while also preparing to defend his thesis in December and start a job at Los Alamos National Laboratory early next year.

Duque probably hasn’t gotten a lot of sleep in the years since he arrived in the United States at the age of 15. It’s hard to shut down a mind so attuned to science that he’s leaped more hurdles in his 31 years than many people will see in a lifetime.

Duque, a Rice doctoral student in the Chemical and Biomolecular Engineering (CHBE) Department, has published his third nanoscience paper, and already it’s old news. He’s on to a fourth and fifth while also preparing to defend his thesis in December and start a job at Los Alamos National Laboratory early next year.

Who needs sleep, anyway?

”If you’re able to manage your time, that’s the best way to get everything accomplished,” said Duque. ”You have to multitask … but when you do something, you have to do it 100 percent.”

Duque’s new work, co-credited to his advisers in CHBE, Professor Matteo Pasquali and senior research fellow Howard Schmidt, deals with the interaction of single-walled carbon nanotubes (SWNTs) with electromagnetic fields. The paper in the Journal of the American Chemical Society describes how SWNTs stabilized in a surfactant (which is, essentially, a soap) along with metal salts become polarized when exposed to microwaves, generating metallic deposits on their tips.

The SWNTs behave much like nanoscale antennas, tiny polarizable structures that can drive electrochemical reactions. They have potential uses in photovoltaics, nanomedicine and synthesis.

According to Schmidt, the work has provided deep insight into the mechanics of electron transfer reactions with SWNTs, which are basic to electrochemical photovoltaics and photocatalysis. He said the reaction could also facilitate separating metallic from semiconducting nanotubes.

”Juan’s been working on this since about five minutes after we met,” said Schmidt. ”He had a very well-rounded chemical engineering background, as well as some electrochemical and microfluidics experience, and he turned out to be a gifted experimentalist.

”He has great hands in the lab — he’s very diligent and he’s able to figure out very quickly when an experiment has been successful, when it has gone wrong and when it’s something special — a consistent anomaly.”

Duque is particularly interested in photovoltaics. Nanotubes that can be tuned to absorb light across the spectrum may be more efficient than any other now available.

Since completing the paper, Duque has found those same nanotubes can be bent into perfect circles in high yield, their ends attracting and attaching, like a dog chasing — and catching — its tail. Such nano-rings were already known in the literature to occur occasionally by agitating particles with sound waves, a process called sonication. The twist here is that they can be induced quickly by exposing the SWNTs to electromagnetic fields under certain conditions. Such rings could be the basis for ultrasensitive sensors, Duque said. ”If you have few electrons flowing around the tube as electric current, then it would be possible to detect small changes on the surface of the nanotubes as current fluctuations,” he said.

Duque has traveled a long and challenging road since leaving his native Medellin, Colombia, for Brooklyn, N.Y., as a teen. Finishing high school there, he lived with two cousins and two uncles, one of whom managed a Park Avenue building 24 hours a day during the week.

He soon found himself working at least one and usually two jobs while pursuing undergraduate studies at City College of New York (CCNY), though he left school with the intention of following his cousins onto the New York City police force.

”I was in the police cadet program for a couple of years, but I found out engineering school was more for me,” he said of his return to CCNY. ”At one point, I worked from midnight to 8 in the morning, and then went to school from 8 to 2 in the afternoon,” he said. A divorce and a cancer scare added to his burden.

Alexander Couzis, now chair of the CCNY Chemical Engineering Department, helped Duque begin to realize his potential. ”I teach an introduction to chemical engineering course and get a good gauge of how aggressive students are, how motivated they are. Juan really struck me as a kid who wanted to work hard,” said Couzis, who admitted to talking Duque out of becoming a cop and into looking at grad school. ”It was very clear to me that Juan was an engineer and scientist. Not that he wouldn’t have been a great police officer, but he’ll serve the community much better as a scientist.”

He also helped Duque win a scholarship that had recently been funded by CCNY graduate Andy Grove, a founder and later CEO of Intel, for top students in need of financial help. ”Juan really benefited from that scholarship,” Couzis said, ”because it allowed him to focus, instead of having to work 40 hours a week while he was in school.”

Pasquali became aware of Duque’s talents through a bit of serendipity. ”I was visiting CCNY to give a seminar in the fall of 2003 and met Alex,” Pasquali recalled. ”At some point, he started telling me about Juan, who had just joined our graduate program.”

At Rice, Duque worked for 2½ years under the tutelage of Paul Laibinis, an associate professor in chemical engineering who has since moved to Vanderbilt University. Knowing Duque was at loose ends without an adviser, Pasquali and Schmidt recruited him for the Carbon Nanotechnology Laboratory to apply his skills to nanotube research. The results speak for themselves. “It worked out better than anyone expected,” said Pasquali. “He has done, in essentially a little less than three years, as much or more than many other students here. It’s very impressive.”

“Everybody knows nanotubes are beautiful conductors,” said Duque, who spent five months earlier this year working on yet another project in the Nanophotonics Laboratory at the University of Bordeaux in France. “They absorb almost everywhere in the spectrum, and they have all these optical and electronic properties. If we can incorporate all of these properties into suitable devices, then nature is actually giving us everything we need to solve our energy problems.”

Schmidt is convinced Duque will bring us ever closer to those solutions in his career at Los Alamos and beyond.

“Losing Juan is like losing an arm,” he said. “But he has a great postdoctoral position lined up — it’s the next step to a great career in science.”