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Joule heating effects on electroosmotic flow in insulator‐based dielectrophoresis
Author(s) -
Sridharan Sriram,
Zhu Junjie,
Hu Guoqing,
Xuan Xiangchun
Publication year - 2011
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.201100011
Subject(s) - joule heating , dielectrophoresis , mechanics , microchannel , electric field , microfluidics , electro osmosis , insulator (electricity) , flow (mathematics) , voltage , materials science , chemistry , nanotechnology , physics , optoelectronics , electrophoresis , chromatography , quantum mechanics , composite material
Abstract Insulator‐based dielectrophoresis (iDEP) is an emerging technology that has been successfully used to manipulate a variety of particles in microfluidic devices. However, due to the locally amplified electric field around the in‐channel insulator, Joule heating often becomes an unavoidable issue that may disturb the electroosmotic flow and affect the particle motion. This work presents the first experimental study of Joule heating effects on electroosmotic flow in a typical iDEP device, e.g. a constriction microchannel, under DC‐biased AC voltages. A numerical model is also developed to simulate the observed flow pattern by solving the coupled electric, energy, and fluid equations in a simplified two‐dimensional geometry. It is observed that depending on the magnitude of the DC voltage, a pair of counter‐rotating fluid circulations can occur at either the downstream end alone or each end of the channel constriction. Moreover, the pair at the downstream end appears larger in size than that at the upstream end due to DC electroosmotic flow. These fluid circulations, which are reasonably simulated by the numerical model, form as a result of the action of the electric field on Joule heating‐induced fluid inhomogeneities in the constriction region.