Physics of Fluids - Publications

Self-wrapping of an ouzo drop induced by evaporation on a superamphiphobic surface

arΧiv
Soft Matter 13, 2749–2759 (2017)
See also Inside cover of that article: Soft Matter 13, 2720 (2017

Authors

	Huanshu Tan
	Christian Diddens
	Michel Versluis
	Hans-Jürgen Butt
	Detlef Lohse
	Xuehua Zhang

BibTeΧ

@Article{C6SM02860H,
author ="Tan, Huanshu and Diddens, Christian and Versluis, Michel and Butt, Hans-Jurgen and Lohse, Detlef and Zhang, Xuehua",
title  ="Self-wrapping of an ouzo drop induced by evaporation on a superamphiphobic surface",
journal  ="Soft Matter",
year  ="2017",
pages  ="-",
publisher  ="The Royal Society of Chemistry",
doi  ="10.1039/C6SM02860H",
url  ="http://dx.doi.org/10.1039/C6SM02860H",
abstract  ="Evaporation of multi-component drops is crucial to various technologies and has numerous potential applications because of its ubiquity in nature. Superamphiphobic surfaces{,} which are both superhydrophobic and superoleophobic{,} can give a low wettability not only for water drops but also for oil drops. In this paper{,} we experimentally{,} numerically and theoretically investigate the evaporation process of millimetric sessile ouzo drops (a transparent mixture of water{,} ethanol{,} and trans-anethole) with low wettability on a superamphiphobic surface. The evaporation-triggered ouzo effect{,} i.e. the spontaneous emulsification of oil microdroplets below a specific ethanol concentration{,} preferentially occurs at the apex of the drop due to the evaporation flux distribution and volatility difference between water and ethanol. This observation is also reproduced by numerical simulations. The volume decrease of the ouzo drop is characterized by two distinct slopes. The initial steep slope is dominantly caused by the evaporation of ethanol{,} followed by the slower evaporation of water. At later stages{,} thanks to Marangoni forces the oil wraps around the drop and an oil shell forms. We propose an approximate diffusion model for the drying characteristics{,} which predicts the evaporation of the drops in agreement with experiment and numerical simulation results. This work provides an advanced understanding of the evaporation process of ouzo (multi-component) drops."}