MSE Seminar

| Title | A Thermotaxis Liquid Actuator

| Speaker | Prof. Hyoung Jin Cho (Department of Mechanical and Aerospace Engineering University of Central Florida)

1989년 서울대 무기재료공학과 학사

1991년 서울대 무기 재료공학과 석사

1993-1997년 전자부품연구소(KETI) 근무

2002년 University of Cincinnati 전기공학 박사

2002-현재 University of Central Florida, 기계항공공학과 교수

Hyoung Jin Cho is a Professor in the Department of Mechanical and Aerospace Engineering at the University of Central Florida. He earned his PhD in Electrical Engineering from the University of Cincinnati in 2002, MS and BS in Inorganic Materials Engineering from Seoul National University in 1991 and 1989, respectively. He worked as Research Engineer at Korea Electronics Technology Institute (KETI) from 1993 to 1997. He was a recipient of NSF CAREER award in 2004. His main research interest is in the development of microscale actuators, sensors and microfluidic components based on MEMS technology.

| Date | 14:00, Friday November 6, 2015

| Place | Bldg. 33  Room 223

| Abstract |

At the microscale, the effect of surface forces become more dominant over convection and other long range body forces, making the fluid actuation by means of capillarity attractive. Thermocapillary describes the change of surface tension of liquids due to a temperature gradient. Although thermocapillary has been studied for long, its practical implementations into working devices have been largely hampered by evaporation, hysteresis, and pinning associated with heating. In our research, an aqueous droplet formed at fluorocarbon oil with air interface could be utilized for dual motions of a newly proposed liquid actuator. A floating droplet as a container could be formed in a metastable energy state and actuated by an immiscible career liquid film underneath. By creating appropriate spatio-temporal thermal gradient maps, a droplet can be transported on controlled pathways with a high level of flexibility and speed. Known disadvantages of traditional thermocapillary manipulation such as low speed, high thermal loading, surface contamination, contact angle hysteresis and evaporation loss could be addressed in this newly proposed thermotaxis liquid actuator.  General solutions for energy and force analysis are presented to explain physics behind this new observation.  The second part of seminar will introduce various research done by my group with a central theme of microscale host devices for nanoscale materials such as graphene actuators, metal oxide gas sensors, and nanoporous metal electrochemical sensors.

| Host | Prof. Chan Park (880-9324)