DC-electrokinetic motion of colloidal cylinder(s) in the vicinity of a wall

Abstract

DC-electrokinetic behavior of colloidal particles in the vicinity of a conducting/non-conducting planar boundary is investigated using an inhouse boundary element method (BEM) based solver in MATLAB R􀀁 environment. In the model, contribu-tion of hydrodynamic drag, electrokinetic (electrophoretic and dielectrophoretic), and colloidal forces (van der Waals and EDL) to over-all particle velocity is com-puted. The electrokinetic and colloidal forces are calculated using prescribed relations obtained from the literature. These forces are then included in the model as external forces acting on the particles. The electrokinetic (EK) forces are obtained by integrating Maxwell stress tensor (MST) over particles’ surfaces. Throughout this work, a thin EDL assumption is made. Position and velocities of the particles along with resulting flow and electric fields are computed. Over-all, results are compared with experimental observations and a general discussion regarding colloidal behavior is made.