Link to the University of Pittsburgh Homepage
Link to the University Library System Homepage Link to the Contact Us Form

Micro-Object Manipulation Using Oscillating Bubbles

Chung, Sang Kug (2011) Micro-Object Manipulation Using Oscillating Bubbles. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

Primary Text

Download (12MB) | Preview


This thesis deals with the development of novel manipulation techniques of micro/mini objects using oscillating bubbles. Two major physical principles studied and applied are cavitational microstreaming flows and electrowetting on dielectric (EWOD) actuation in gaseous bubbles. Micro/mini bubbles oscillated and handled in 2-D and 3-D spaces using these two principles are key components serving as carriers of objects to be manipulated. The first type of manipulation system allows us to manipulate mini/micro objects on a 2-D space. A series of bubble operations (creation, elimination, and transportation) and object manipulations (capturing, carrying, and releasing) is extensively investigated in this configuration along with modeling and analysis. The capturing force is identified and completely confirmed as the acoustic radiation force through several experiments. Effects of the frequency and amplitude of acoustic excitation on capturing are quantified with high-speed imaging. The bubble elimination process is modeled by two sequential steps: catalytic reaction and dissolving process.In addition, the similar operations of capturing, carrying, releasing of objects are accomplished only using AC-EWOD, not using the acoustic excitation. In this case, the AC voltage (optimal frequency of 100 Hz) not only oscillates the bubble but also transports the oscillating bubble on the surface. However, the carrying efficiency is lower than the simultaneous actuations of acoustic excitation and EWOD. The second type of object manipulation system utilizes the capturing phenomenon by oscillating bubble. The main feature is that the oscillating bubble is deposited on a 3-D traversing rod tip, rather than a two-dimensional surface. So, it allows for object manipulation in a 3-D space. It is concluded from multiple experiments that the maximum carrying speed is highest near the bubble resonant frequency, meaning that the capturing force is proportional to the bubble oscillation amplitude.Finally, the cavitational streaming flow is extended to underwater propulsion. The key concept is to utilize the net momentum flux around the oscillating bubble. As a reaction force, the net momentum flux pushes or pulls the solid substrate on which the oscillating bubble sits. Using mini/micro glass rods, the propulsion mechanism is experimentally proved. The propulsion force is measured to be hundreds of nano-Newtons in a pendulum configuration.


Social Networking:
Share |


Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Chung, Sang
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairCho, Sung Kwon
Committee MemberKim, Kang
Committee MemberSchaefer, Laura
Committee MemberChyu, Minking K
Date: 3 August 2011
Date Type: Completion
Defense Date: 15 June 2009
Approval Date: 3 August 2011
Submission Date: 20 July 2009
Access Restriction: 5 year -- Restrict access to University of Pittsburgh for a period of 5 years.
Institution: University of Pittsburgh
Schools and Programs: Swanson School of Engineering > Mechanical Engineering
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: Cell manipulation; electrowetting; microfluidics; oscillating bubble; underwater propulsion
Other ID:, etd-07202009-140517
Date Deposited: 10 Nov 2011 19:52
Last Modified: 15 Nov 2016 13:46


Monthly Views for the past 3 years

Plum Analytics

Actions (login required)

View Item View Item