Dielectrophoretic technique for separation of o/w nanoemulsion

Dielectrophoresis (DEP) is an efficient electro-kinetic technique with great potential for demulsification. We present an experimental study to the dynamic behavior of particles under DEP using AC-electric field. DEP is produced by polarization effects when particles are exposed to non uniform electric field. DEP is applied to remove of sunflower oil-particles in nanometer scale which have dispersed to the water [oil in water emulsion (o/w)]. In a DEP field the polarized particles experience a force that can cause them to move to regions of high or low electric field,depending on the particle polarizability (electrical conductivity) compared with the suspendingmedium. According to the low conductivity (using electrical conductivity measurement) ofdispersed phase (oil conductivity) in comparison to water as continuous phase, DEP-force will tend to move the particles towards the weakest or minimum region of the electric field (dd −dc = - 0.095), the negative number means, it is about a negative-dielectrophoretic process (n-DEP). The oil-particle size is shown using AFM (Atomic force microscope) between 25 nm to 250 nm. The largest part of particles is between 50 nm to 60 nm.

Keywords:

Dielectrophoresis , Separation , o , w Emulsion , Non-uniform electric field