Fri August 24th 2018
10:30 – 11:30
ZH286
Seminar Production of nanodroplets via solvent shifting in a microfluidic device
Steffen Hardt

Details:

Droplet production in a microfluidic co‐flow device using a ternary liquid system was studied experimentally. A co‐flow configuration with a mixture of ethanol and oil as the core flow and water as the annular flow was employed. Diffusive mass transfer between ethanol and water creates a region where the oil component is in a supersaturated state. As a result, oil droplets nucleate, similar to what happens when the Greek anise‐flavored aperitif Ouzo is diluted with water. After the droplets have been produced, they migrate toward the channel centerline, presumably driven by solutal Marangoni
stresses. At a downstream position the droplets get collected in a thin thread at the channel centerline composed of a multitude of densely packed droplets. The phase‐change and transport phenomena observed inside the channel are explained by referring to the phase diagram of the water‐ethanol‐oil system.
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