ELECTRICAL TOMOGRAPHY SENSING AND DIELECTROPHORESIS IN MICROCHANNEL FOR 3D PARTICLE MIXING

The present study describes the electrical tomography sensing and dielectrophoresis (DEP) force for visualize the 3D particle mixing in the microchannel system. In the presence of non-uniform electric fields generated by point microelectrodes, the dynamic distribution behaviors of a polystyrene particle and deionized water had been investigated in this system. Microchannel was fabricated with five cross sections where 12 electrodes were installed for each measurement plane. In this experiment, the relationship between electric field frequency and DEP force of particles are calculated at different electric frequencies and diameter of particles. The applied electric field intensities are E=+/- 1 V/mm, +/- 3 V/mm and +/- 5 V/mm while the electric field frequencies are f=1 kHz, 10 kHz, 100 kHz and 1 MHz and the diameter of particles are 1.3 mu m, 1.5 mu m and 2.0 mu m are investigated in this experiment. Simultaneously, imaged by manipulating tomography sensing at cross section A, C and D and the coupled DEP forces at cross section B and D, the particles flowing had been visualized and concentrate uniformly at near the outlets. The electrical capacitances and DEP forces between the electrode pairs of the microchannel were measured and the ECT tomograms representing the particle distribution were constructed from the measured capacitance data for each cross section in microchannel.