Authors: R. Miraghaie, J.D. Sterling and A. Nadim
Affilation: Keck Graduate Institute, United States
Pages: 610 - 613
Keywords: droplet microfluidics, electrowetting, mixing
We show that internal mixing within a sessile liquid drop can be significantly enhanced by means of so-called electrowetting-on-dielectric (EWOD), using an alternating electric potential. This is done experimentally by comparing the coalescence and mixing of two dyed liquid drops that are brought together by electrowetting actuation. To understand the internal mixing, which appears to be driven by shape oscillations of the sessile drop, we also conduct detailed experimental and analytical studies of the shape oscillations of drops that are attached to a planar solid surface. We show that depending on the frequency of the applied alternating field, single or multiple modes of oscillation may be excited.