Dresden 2020 – scientific programme
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O: Fachverband Oberflächenphysik
O 116: Wetting and Liquids at Interfaces and Surfaces II (joint session CPP/DY/O)
O 116.3: Talk
Friday, March 20, 2020, 10:15–10:30, ZEU 260
Formation of a thin film during drop merging leads to fingering instability — •Peyman Rostami1,2 and Günter Auernhammer1,2 — 1Max Planck Institute for Polymer Research, 55128, Mainz, Germany — 2Leibniz Institute of Polymer Research, 01069, Dresden, Germany
The coalescence and interaction between two drops have been the subject of intensive studies in recent years [1], due to its wide range of application and the presence in the nature.
Here, we study the merging of partially miscible drop. We deposit drops of different liquids on a substrate. Under appropriate conditions, the merging process generates an instability which resembles the Rayleigh-Plateau instability. If the liquid with higher surface activity is deposited as a second droplet. Its vapor can diffuse through the air and induce a Marangoni flow inside the already deposited droplet. This induced flow can pull a thin liquid layer over the surface , which decays into drops by a Rayleigh-Plateau instability.
We present a detailed study of this instability analyzing the onset of the instability and its characteristic length scales. Finally, a model is presented to explain the Marangoni flow induced by the gas phase. This model is validated by particle tracking.
References [1] S. Karpitschka, C. Hanske, A. Fery, and H. Riegler, Langmuir, vol. 30, no. 23, pp. 6826*6830, 2014.