Wed March 18th 2015
16:00 – 17:00
Seminar Manipulation of drops with electrowetting: From morphological transitions to microfluidics
Riëlle de Ruiter


In electrowetting, the effective wetting properties of a substrate are modified by applying an electric field. Practical applications can for example be found in lab-on-a-chip devices, liquid lenses, and electronic displays.

Due to the fast and reversible variations in contact angle, electrowetting is a convenient experimental technique to study morphological transitions of liquid drops in various geometries. In this presentation, I will first discuss the equilibrium shapes of drops confined between a sphere and a plate – representing a pore throat in oil recovery problems – and drops wetting a fiber. A combination of experiments and numerical calculations allows us to determine the stability limits of the different morphologies, the type of the transitions between them, and the effect of even minor degrees of contact angle hysteresis.

Secondly, I will discuss the use of tunable electrical traps as a new tool in continuous-flow microfluidics. Combining the individual drop control achieved using electrical actuation with the high throughput of channel-based microfluidics enables several drop manipulations that are important for many lab-on-a-chip applications, such as on-demand drop trapping and release, guiding, and high-speed sorting.
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The 10th Complex Motion in Fluids 2021
Max Planck Gesellschaft
Centre for Scientific Computing