Dielectrophoretic Control of Bubble Transport in Mesochannels— Experimental Study

Abstract

Using electrostatic fields to manipulate and/or pump fluids on the microscale is a promising method for the advancement in microfluidics. Preliminary analysis showed that unidirectional bubble motion could be achieved if the polarization (dielectrophoretic) force could overcome surface tension and viscous forces. Results are presented for the development and fundamental study of dielectrophoretic control of bubble transport in mesochannels. Electrode array configurations were manufactured using printed circuit board technology and mated with an acrylic channel. Bubble velocity, acceleration, and deformation were investigated for a range of bubble sizes, two electrode array configurations, two working fluids—pentane and a 20/80 mixture by mass of ethanol and pentane, two switching frequencies, and a range of +DC pulse applied voltages. A maximum average velocity of 6.6mm∕s and a maximum local velocity of 30mm∕s were achieved. For the results presented, both the switching frequency and bubble size affected the velocity for a given applied voltage. Of the two fluids tested, there was no measurable difference in the bubble velocity even though the bubble deformation was significantly different for the two fluids. It was concluded that bubble deformation reduced the unidirectional bubble motion effectiveness. Bubble deformation could be reduced by lowering the applied voltage without significantly reducing the velocity of the bubble.