DIELECTROPHORETIC INVESTIGATIONS OF SUBMICROMETER LATEX SPHERES

A non-uniform AC electric field induces a motion in polarizable partic les, called dielectrophoresis. The force responsible for this motion i s governed by the dielectric properties both of the suspending medium and of the particles, as well as the geometry of the field. The dielec trophoretic properties of sub-micrometre latex spheres have been studi ed using micro-fabricated electrode structures. The electric field geo metry for electrodes used in the measurements has been solved using nu merical analysis. Measurements of the dielectrophoretic properties of the spheres have been made over a range of medium conductivities and a pplied field frequencies and strengths. Comparisons between the observ ed behaviour and that expected from theory are presented.