COLLEGE STATION, Texas - Dr. Jaime Grunlan, an assistant professor in the Department of Mechanical Engineering at Texas A&M University, has received a 2007 National Science Foundation (NSF) CAREER award for his research into controlling the microstructure of high aspect ratio nanoparticles (e.g., carbon nanotubes) using stimuli-responsive polymers.

The $400,000 grant will continue through 2012.

Nanoparticles have desirable properties for use in electronics and medical diagnostic applications. The problem is, Grunlan said, that at the nano level, the particles' properties change dramatically.

"In theory, we should get amazing properties with nanoparticles, but we're not getting those," Grunlan said. "We have no control over the particle behaviors in solution or in a composite."

Until now. Grunlan said he has developed a way to control the nanoparticles in terms of how they organize themselves, either clumping up (aggregating) or spreading apart (exfoliating). When nanoparticles clump together, they no longer have desirable behavior because they're no longer nanoparticles but are rather larger particles. But Grunlan can tune the nanoparticles to give them a particular level of aggregation or exfoliation by changing some stimulus - for instance, temperature or light - to make the particles behave differently.

Grunlan's CAREER award comes on the heels of a recently published article (Grunlan et al. Nano Letters 2006, 5, 911-915) describing the ability to tailor the microstructure of carbon nanotubes in a water-based suspension and in solid composites. The key to this work, Grunlan said, is the use of a stimuli-responsive polymer whose interaction with the nanotube changes as the stimulus is changed. Initial work was done with poly(acrylic acid), using pH as the stimulus, but with the CAREER Award, Grunlan will focus on a variety of stimuli (temperature, light, glucose, etc.) and nanoparticles (silver nanowires, carbon nanotubes, etc.).

Grunlan said his work will lead to new classes of lightweight engineering composites for applications such as microwave antenna substrates; sensing and actuation transducers for biomedical applications; and highly conductive, flexible microelectronic materials.

"We have to be able to get the material to do what we want it to do," Grunlan said, "and this is a key step toward that."

In addition to being on the mechanical engineering and materials science and engineering faculties, Grunlan is also a researcher in the Polymer Technology Center of the Texas Engineering Experiment Station, the engineering research agency of the State of Texas and a member of The Texas A&M University System. His Polymer Nano Composites Lab is currently developing thick and thin film polymer nanocomposites for a variety of applications that include EMI shielding, gas permeation control and sensors.

Grunlan joined the Department of Mechanical Engineering in 2004. He received a bachelor's degree from North Dakota State University and a Ph.D. from the University of Minnesota.

For more information, contact

Reporter: Lesley Kriewald
lesleyk@tamu.edu
(979) 845-5524

News Story 1435, March 22, 2007

Direct page link:
http://engineeringnews.tamu.edu/news/1435

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