NUMERICAL STUDY OF DIELECTROPHORESIS FORCE IN THE ISOLATED ELECTRODE: A COMPARATIVE APPROACH

Abstract

One of the general methods for particle separation in lab-on-a-chips (LOCs) is dielectrophoresis (DEP). The effects of electrode isolation in DEP-based particle separation devices are discussed throughout this paper. One advantage of the electrode isolation is reducing electrode–electrolyte–sample mutual interactions. In this study, the conventional DEP forces using interdigitated electrode arrays is numerically investigated without and in the presence dielectric layer in the interface of electrode and electrolytic fluid. The study includes the effect of dielectric layer thickness when fluids of different electrical conductivity are involved. The results show that the electric field and also intra-channel gradient of electric field square depend on frequency and an isolating layer acts as high-pass filter, thus frequency response of conventional DEP force besides Clausius–Mossotti (CM) factor is depended on the electric field gradient. The results also show that in contactless model, the frequency response of the DEP forces can be engineered by dielectric thickness and electrical conductivity of the suspending medium. According to the obtained results, during particle separation with DEP method in the presence of insolated electrodes and considering the reduction in electric field intensity, an appropriate and optimal choice for working frequency, voltage of electrodes and thickness of dielectric layer should be considered. The particles and dielectric isolated layer under study is polystyrene beads and polydimethylsiloxane (PDMS) elastomeric polymer, respectively.