Transient Electrophoretic Motion of a Charged Particle through a Converging-Diverging Microchannel: Effect of Direct Current-Dielectrophoretic Force

Document Type

Article

Publication Date

7-2009

Publication Title

Electrophoresis

Volume

30

Issue

14

First page number:

2499

Last page number:

2506

Abstract

Transient electrophoretic motion of a charged particle through a converging–diverging microchannel is studied by solving the coupled system of the Navier–Stokes equations for fluid flow and the Laplace equation for electrical field with an arbitrary Lagrangian–Eulerian finite-element method. A spatially non-uniform electric field is induced in the converging–diverging section, which gives rise to a direct current dielectrophoretic (DEP) force in addition to the electrostatic force acting on the charged particle. As a sequence, the symmetry of the particle velocity and trajectory with respect to the throat is broken. We demonstrate that the predicted particle trajectory shifts due to DEP show quantitative agreements with the existing experimental data. Although converging–diverging microchannels can be used for super fast electrophoresis due to the enhancement of the local electric field, it is shown that large particles may be blocked due to the induced DEP force, which thus must be taken into account in the study of electrophoresis in microfluidic devices where non-uniform electric fields are present.

Keywords

Arbitrary Lagrangian–Eulerian; Dielectrophoresis; Electric fields; Electrophoresis; Lab-on-a-chip; Microfluidics; Particles (Nuclear physics)

Disciplines

Atomic, Molecular and Optical Physics | Electromagnetics and Photonics | Electro-Mechanical Systems | Mechanical Engineering

Language

English

Permissions

Use Find in Your Library, contact the author, or interlibrary loan to garner a copy of the item. Publisher policy does not allow archiving the final published version. If a post-print (author's peer-reviewed manuscript) is allowed and available, or publisher policy changes, the item will be deposited.

UNLV article access

Search your library

Share

COinS