Microfluidic transport based on direct electrowetting

An integrated microfluidic system was fabricated which functions by deliberately manipulating interfacial tension. A distinctive characteristic of our system is the use of an array of adjacent, elongated, working electrodes and protruding polydimethylsiloxane open-flow channels. Microfluidic transport was realized directly on the bare gold electrode surface in the absence of an additional dielectric layer. By changing the potential of the working electrode to a negative potential, a liquid column could be transported from one end of an elongated working electrode to the other end. Transport of the liquid column could be altered without any valves by switching on the adjacent electrode in a given direction. The flow velocity depended on the applied potential, i.e., the velocity could be altered by deliberate manipulation of the electrode potential. In addition, the flow velocity increased as the dimensions of the flow channel decreased. The applied voltage was less than 2 V, and the power consumption was in the order of tens of muW. (C) 2004 American Institute of Physics.