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


Zhao, Yuejun (2008) MICROPARTICLE SAMPLING AND SEAPARATIONENABLED BY DROPLET MICROFLUIDICS. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

Primary Text

Download (2MB) | Preview


This work reports design, device fabrication, modeling and experimental results on newsampling and separation principles in which liquid is transported in a droplet form on a plannerhydrophobic surface with no moving parts. The presented particle sampler and separatorconstitute core units for the handheld lab-on-a-chip-based airborne particle monitoring system.For the airborne particle sampling, a novel method is developed by which the particles onthe solid surface are swept and sampled by electrowetting-actuated moving droplets. Theoreticalanalysis and experimental works along with microfabricated testing devices are carried out toinvestigate the underlying physics and to optimize the sampling conditions. The samplingconcepts are examined and proved on a solid surface and perforated filter membrane showinghigh sampling efficiencies.For the particle separation, a new separation scheme is developed in which the mixedparticles are separated within a mother droplet by traveling-wave dielectrophoresis (tw-DEP).Using the subsequent operation of droplet splitting by way of electrowetting, the separatedparticles can be isolated into each split droplet according to the DEP properties of the particles.This in-droplet separation is examined with many combinations of particles in microfabricateddevices. By investigating the particle behavior as function of the frequency of the traveling waveDEP signal, the separation efficiencies are optimized.The above microfluidic units constitute key components for upstream particle sampling anddownstream sample processing in the lab on a chip system, providing the following advantages:extremely small amount use of samples/reagents (2) no external pressure source required forfluidic operations, (3) simple design and fabrication since no mechanical moving structure.


Social Networking:
Share |


Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Zhao, Yuejunyuz21@pitt.eduYUZ21
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairCho, Sung Kwonskc@engr.pitt.eduSKCHO
Committee MemberBarnard, John Ajbarnard@engr.pitt.eduJBARNARD
Committee MemberYun, Minheeyunmh@engr.pitt.eduMIY16
Committee MemberChyu, Minking Kmkchyu@engr.pitt.eduMKCHYU
Date: 8 September 2008
Date Type: Completion
Defense Date: 18 July 2008
Approval Date: 8 September 2008
Submission Date: 29 July 2008
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
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: digital microfluidics; perforated membrane; traveling wave DEP
Other ID:, etd-07292008-161949
Date Deposited: 10 Nov 2011 19:54
Last Modified: 15 Nov 2016 13:47


Monthly Views for the past 3 years

Plum Analytics

Actions (login required)

View Item View Item