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Scaling law analysis of electrohydrodynamics and dielectrophoresis for isomotive dielectrophoresis microfluidic devices
Author(s) -
Rashed Mohamed Z.,
Green Nicolas G.,
Williams Stuart J.
Publication year - 2020
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.201900311
Subject(s) - dielectrophoresis , electrohydrodynamics , electrokinetic phenomena , electric field , particle (ecology) , microfluidics , microchannel , polarizability , materials science , scaling , voltage , mechanics , nanotechnology , molecular physics , physics , oceanography , geometry , mathematics , quantum mechanics , molecule , geology
Isomotive dielectrophoresis (isoDEP) is a unique DEP geometrical configuration where the gradient of the field‐squared ( ∇ E rms 2 ) is constant. IsoDEP analyzes polarizable particles based on their magnitude and direction of translation. Particle translation is a function of the polarizability of both the particles and suspending medium, the particles’ size and shape, and the frequency of the electric field. However, other electrokinetics act on the particles simultaneously, including electrothermal hydrodynamics. Hence, to maximize the DEP force relative to over electrokinetic forces, design parameters such as microchannel geometry, fabrication materials, and applied electric field must be properly tuned. In this work, scaling law analyses were developed to derive design rules, relative to particle diameter, to reduce unwanted electrothermal hydrodynamics relative to DEP‐induced particle translation. For a particle suspended in 10 mS/m media, if the channel width and height are below ten particle diameters, the electrothermal‐driven flow is reduced by ∼500 times compared to a channel that is 250 particles diameters in width and height. Replacing glass with silicon as the device's underlying substrate for an insulative‐based isoDEP reduces the electrothermal induced flow approximately 20 times less.