Cottrell College Science Awards - 2015
Investigation of Magnetoviscous and Viscoelastic Properties of Micro to Nanoliter Ferrofluids
Advanced research often requires advanced technology, and creating that technology often requires, well, advanced research.
Which is why Yu Gu, assistant professor of physics at Saint Joseph’s University, has received a Cottrell College Science Award from Research Corporation for Science Advancement (RCSA). Gu is working to understand the subtle properties of tiny droplets of oil and water that contain suspended nanoparticles of iron.
These droplets are called “ferrofluids” and they are seeing increasing use in the high-impact field of Lab-On-Chip devices -- miniaturized chemical and biochemical platforms that perform near-instant analysis. Ferrofluids have been used to pump microscopic samples in DNA amplification and in sorting individual cells. They are also being used to improve efficiencies in drug delivery and tumor treatment.
“Because ferrofluids react to external magnetic fields by changing liquid viscosity and surface energy, they can be actuated without the use of moving parts,” Gu says. She notes that viscosity and surface tension are important qualities to control because, in order to do their work, ferrofluids sometimes must flow through channels that are tens of microns wide, which is one-hundred-thousandth of a meter, the size scale of the width of a human hair. The tiniest change in a ferrofluid’s viscosity or surface tension can dramatically affect flow through micron scale channels.
Specifically, Gu and her students will be studying the viscous and elastic properties of various ferrofluids as they travel along microfluidic channels under the influence of external oscillating magnetic fields. They hope to determine the maximum possible oscillation frequency under which the droplets will move without breaking up. To do so, they will monitor behavior of the ferrofluids in milliseconds and track them with microscope cameras.