The effect of dielectric constant on particle-particle dielectrophoretic attraction in dielectric fluids

The aim of this study was to investigate how the particulate phase dielectric constant impacts the dielectrophoretic force in an organic fluid suspension. This was accomplished through the construction of an apparatus which allowed the direct measurement of the dielectrophoretic force of attraction between macroscopic ceramic hemispheres submerged in an uncrosslinked thermoset polyurethane carrier fluid. The analysis of the experimental data show that the dielectrophoretic force increases with particle dielectric constant under AC fields but the same relationship does not hold when applying DC fields. This is believed to occur owing to the relaxation of the conduction mechanism under an alternating electric field.