Modeling of DC-electrokinetic motion of colloidal cylinders in the vicinity of a wall

The electrokinetic behavior of the particles in a microchannel is widely investigated due to their potential use in microfluidic applications such as separation or characterization of bio-molecules, bacteria, self-assembly processes etc. In this study, DC-electrokinetic behavior of colloidal particles in the vicinity of a conducting/non-conducting planar boundary is investigated using an inhouse boundary element method based solver. The contribution of hydrodynamic drag, electrokinetic (both electrophoretic and dielectrophoretic), and colloidal forces (van der Waals and EDL) to overall particle velocity is assessed. The colloidal forces are calculated using prescribed relations obtained from the literature, and included in the model as external forces acting on the particles. The electrokinetic forces are obtained by integrating Maxwell stress tensor over particles' surfaces. Position and velocities of the particles along with resulting flow and electric fields are computed. Overall, results are compared with experimental observations and a general discussion regarding colloidal behavior is presented.