Abstract: Liquid handling and actuation by means of controlling surface tension has proven to have many advantages in small-scale applications due to the surface tension force dominance over body forces. In 1875, Lippmann first explored the phenomenon of the surface tension modulated with an electric field, which is called an electrowetting effect. When an electric potential is applied between a liquid and a solid electrode, the charge redistribution modifies the surface tension at the liquid−solid interface where the like-charge repulsion decreases the work by expanding the surface area. Due to the benefits of large forces in micro/meso scales, a fast response time in the range of microseconds, and low-power operation, the electrowetting technology has been used for numerous applications, including lab-on-a-chip, electronic display, thermal management, energy harvesting, and surface science.
In this talk, a broad perspective of the electrowetting technology will be presented from materials to its optics and solar applications. A novel high-capacitance dielectric material, called an ion gel, will be first discussed. Not only it offer 2 to 3 orders higher capacitance (c ≈ 10 μF/cm2) than that of conventional dielectrics such as SiO2, but also is simply fabricated by either a spin or dip-coating method. This high-capacitance ion gel dielectric is used for an electrowetting-driven liquid prism to achieve low-voltage and tunable beam steering performance. We further introduce an arrayed form of the liquid prisms for optics and solar applications such as a tunable Fresnel lens and solar indoor lighting.
Bio: Dr. Sung-Yong Park is an Assistant Professor in the Department of Mechanical Engineering at National University of Singapore (NUS). Before joining NUS, he was a research scientist at Teledyne Scientific Company (formerly known as Rockwell Science Center) where he led several cutting-edge R&D projects funded by ARPA-E, NASA, and Rockwell Automation. He received his doctoral degree from UCLA in 2010 (advisor: Prof. Eric P.Y. Chiou) and was further trained as a post-doctoral researcher at the UCLA Optofluidic Systems Laboratory.
His research interest is generally in the area of optofluidics for energy/water/bio-related applications. He was awarded the 2010 Harry M. Showman Prize, which was given to the very only outstanding graduate student who has the best academic and research achievements from the Class of 2010 graduates in the Henry Samueli School of Engineering and Applied Science at UCLA. He was also a recipient of the Graduate Student Researcher Scholarship from the UCLA Mechanical Engineering department, 2006.
Date(s) - Jun 09, 2017
11:00 am - 12:00 pm