Multiphase Actuation of AC Electrothermal Micropump.

Electrothermal micropumps apply an AC electric field to a conductive fluid within the range of 10 kHz-1 MHz to generate fluid flow. In this frequency range, coulombic forces dominate fluid interactions over opposing dielectric forces, resulting in high flow rates (~50-100 μm/s). To date, the electrothermal effect-using asymmetrical electrodes-has been tested only with single-phase and 2-phase actuation, while dielectrophoretic micropumps have shown improved flow rates with 3- and 4-phase actuation.