277261 Drop Dynamics Between Plate-Pin Electrode

Wednesday, October 31, 2012: 5:30 PM
406 (Convention Center )
Sameer Mhatre, Chemical Engineering, IIT Bombay, Mumbai, India and Rochish Thaokar, Department of Chemical Engineering, Indian Institute of Technology, Bombay, Mumbai, India

In electrophoresis a charged drop migrate to the electrode of opposite polarity and depending on applied electric field strength it undergoes periodic motion between electrodes. A drop undergoes simultaneous deformation and dielectrophoresis when put in the commonly used pin-plate electrode system. An uncharged conductor drop undergoes dielectrophoretic motion to the pin electrode, simultaneously undergoing deformation. It acquires a charge at the pin electrode and is attracted to the plate electrode. Depending upon the voltage applied, the drop can either undergo oscillations around the pin-electrode or oscillations between the two electrodes. The frequency of these oscillations depends upon the applied voltage. The drop deformation and dielectrophoresis are found to be in reasonable agreement with the theory. A phase diagram is constructed depicting these different regimes.  We also report the interplay of two oscillating droplets and their response to the applied electric field. The findings can be useful in applications like electric field-assisted heat and mass transfer, micro-reactors, microfluidics and in atomization techniques.

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