Parting a tiny red sea at the University of Cincinnati: Todays and tomorrows sophisticated electronic devices may hinge on our ability to control microdrops of liquid on a surface. This effect, called electrowetting, controls the contact angle of a liquid on a hydrophobic surface through the use of an electric field.
Diagram and photograph of red-tinted oil being separated by electric current.
As recently published in Applied Physics Letters and featured on the cover of the journal, Andrew Steckls research on liquid-state-field-effect transistors (LiquiFETs) promises improvements in such things as "lab on a chip" devices. These tiny devices, reminiscent of the "Fantastic Voyage," can be introduced into the blood stream to monitor the bloods chemistry. Steckl, a professor in the Department of Electrical and Computer Engineering in the College of Engineering, calls it "liquid logic" using liquids to make electronic devices instead of solids.
One of the limitations of traditional health care instruments, for example, is that the information contained in the liquid (blood, in this example) must be translated into electrical signals that can be read in some kind of measuring device. Classical methods for this "translation" have used methods based on light and colorimetric measurement, direct optical sensing (using a video camera or detector) or combinations of optical excitation of fluorescent dyes.
Professor Andrew Steckl and doctoral student Duk Young Kim with the LiquiFET set-up.
Enter the liquid-state-field-effect transistors (LiquiFETs). Steckl and his doctoral student Duk Young Kim have designed and fabricated an electrowetting-based LiquiFET that operates in the liquid state and can directly convert charge-related information from the fluid into electronic, measurable signals. Such a device could co-exist in human body environment, for example, which is mostly liquid.