Recent developments in microfluidics and analytical chemistry have spurred renewed interest in electrokinetic manipulation of colloidal particles. In this work we investigate the dynamics of a suspension of conducting rods in an applied electric field, in the limit thin electrical double layers. The theory by Bazant and Squires for induced-charge electroosmosis [1, 2] is extended to high-aspect ratio particles to derive a simple model for the induced flow on the particle surfaces. Simulations are performed that include multi-body hydrodynamic interactions, and results are reported for orientation distributions and pair distribution functions. In particular, the pair distribution functions indicate that particle pairing occurs in the suspension as a result of the induced electroosmotic flow. A simple two-particle analytical model is derived for the pairing.

Volume Subject Area:
Fluids Engineering
Topics:
Electrophoresis, Engineering simulation, Particulate matter, Simulation, Electroosmosis, Chemistry, Dynamics (Mechanics), Electric fields, Electrokinetics, Flow (Dynamics), Microfluidics, Rods
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