DIELECTROPHORETIC FORCE CALCULATION

The dielectrophoretic force on insulating and finite conducting dielectric spheres immersed in a dielectric fluid medium and subjected to a non-uniform electric field is calculated using various methods. The first to be considered is the force exerted by a point charge on an insulating dielectric sphere. Next, the total force on a finite conducting dielectric sphere in a finite conducting dielectric fluid is determined. In this latter case, both conduction (free) charge and polarization (bound) charge contribute tothe net effective dipole moment. The various derivations illuminate the conventional approximations used in the dielectrophoretic model. The relationship of free and bound surface charge to the effective dipole moment, to the induced dipole moment and to the total dielectrophoretic force is clarified. © 1979.