Rotating flow within a droplet actuated with AC EWOD

Rachid Malk (1) , Yves Fouillet (1) , Laurent Davoust (2, 3)

1 CEA - Commissariat à l'énergie atomique et aux énergies alternatives
2 LEGI - Laboratoire des Écoulements Géophysiques et Industriels [Grenoble]
3 SIMaP - Science et Ingénierie des Matériaux et Procédés

Electrowetting-on-dielectric (EWOD) is now used in numerous microsystems like digital lab-on-chips. This paper deals with a characteristic hydrodynamic flow appearing in droplets actuated by EWOD with AC voltage. In the coplanar electrode configuration, two pairs of vortex flows are observed to form in a droplet centred on the electrode gap. All experiments are performed in oil as ambient phase and flows in the droplet are analysed using fluorescent beads. At the same time, droplet oscillations induced by AC EWOD are also revealed under stroboscopic lighting. These experiments show that vortex location can be controlled by frequency actuation with fair degree of reproducibility.

Domaines: Matériaux

Rachid Malk, Yves Fouillet, Laurent Davoust. Rotating flow within a droplet actuated with AC EWOD. Sensors and Actuators B: Chemical, 2011, 154 (2), pp.191-198. ⟨10.1016/j.snb.2009.12.066⟩. ⟨hal-00640195⟩