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Fluid Dynamics
Colloquium
Monday, November 14, 2005,
4:00 pm
Cullimore Lecture Hall, Room 611
New Jersey Institute of
Technology
Complex Electrokinetic/Electrohydrodynamic Flows
in Microfluidic Applications
Hao Lin
Assistant Professor
Department of Mechanical and Aerospace Engineering, Rutgers
University, New Brunswick
Electrokinetic flow is leveraged in a variety of microfluidic systems, and is a key enabler of on-chip electrophoretic processes with chemical and bio-analytical applications. The electromechanical coupling of electric field and electrolyte solution in these applications may sometimes lead to novel flow behavior as well as complex electromigration patterns. In this work I will explore two related subjects: electorkinetic instability, and electrophoretic preconcentration methods. Electrokinetic instability (EKI) widely occurs when a heterogeneous buffer is subject to strong applied electric fields. Although undesirable for on-chip assays where controlled sample management is required, EKI is also proposed as efficient means for rapid micromixing which is intrinsically difficult for low-Reynolds number, micro-scale flows. I will present analysis, simulations, experimental observations, as well as reduced modeling results on this topic. For sample preconcentration methods, I will focus on the development of high-fidelity simulation tools for electrophoregram predictions in on-chip electrophoresis, with application towards the design and optimization of detection and separation processes. I will explore the characteristics of different methods such as field-amplified sample stacking and isotachophoresis. I will also discuss the issues and challenges en route to the efficient and accurate modeling of this class of phenomena.