Electrokinetics plays an important role in facilitating fluid transport and particle manipulation in microfluidic systems. This dissertation studies the mechanics of electrokinetic phenomena for microscale particles and drops. The work aims to increase the understanding of complex electrokinetic phenomena for applications in Lab-on-Chip technology, assembly of colloidal particles and two-phase flow sensing. The standard model consisting of the Poisson-Nernst-Planck equations is used to study the electric double layer polarization of charged dielectric particles and channel wall which plays a major role in control and manipulation of colloidal particles and understanding of electrohydrodynamic flow field.The cases of polarization of u22softu22 particle under the influence of alternating current field, influence of residual charges and particle size on electrostatic interaction between charged particles at oil-water interface, and characterization of streaming potential due to drop deformation for a two phase steady flow are modeled and simulated. The theoretical predictions were compared and favorably agree with analytical and experimental observations. The study provides insights to the electrokinetic behavior of micro particles and drops in response to electric fields and pressure driven hydrodynamics respectively. It also helps to quantify the mechanics of colloidal assembly for monolayered geometry. Implementation of above ideas can improve the designs of devices used for sensing, control and manipulation in microfluidic systems.
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