AC electrokinetics - encompassing dielectrophoresis, electrorotation and travelling wave dielectrophoresis - is the phenomenon of induced motion of colloidal particles through the application of AC electric fields. Motion may be induced in either rotational or translational senses, and the nature of the induced force is dependent on the time-dependent morphology of the electric field, as well as the dielectric characteristics of the particle and the suspending medium.
The work presented in this thesis is concerned with the examination of the underlying principles of this phenomenon in a variety of practical applications through the medium of computer simulation. Various computer models are described, with the two used for the simulations presented here being described in greater detail. Applying these models to separate cases of dielectrophoresis, electrorotation and travelling wave dielectrophoresis, the nature of the force distributions may be studies. This allows a more thorough study of such phenomena than is possible through the experimental study of particle motion.
A primary function of this work is to examine the means of optimising electrode design for particle manipulation, separation and characterisation through the application of AC electrokinetic forces. As a consequence of this study, the underlying principles of force distribution have become apparent. In many cases, the detailed study of electric fields and forces generated near the electrodes have demonstrated previously unknown particle behaviours, many of which have been confirmed by experimentation.