Evaporation-triggered microdroplet nucleation and the four life phases of an evaporating Ouzo drop
| Autor: | Huanshu Tan, Christian Diddens, Detlef Lohse, Pengyu Lv, Xuehua Zhang, Jgm Hans Kuerten |
|---|---|
| Přispěvatelé: | Physics of Fluids, Power & Flow, Group Kuerten |
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Phase transition
Evaporation Nucleation FOS: Physical sciences 02 engineering and technology engineering.material 01 natural sciences Oil drop experiment Sessile droplets Coating Ouzo effect 0103 physical sciences Organic chemistry 010306 general physics Different volatilities Multidisciplinary Chemistry Drop (liquid) Fluid Dynamics (physics.flu-dyn) Physics - Fluid Dynamics 021001 nanoscience & nanotechnology Chemical engineering Oil droplet Physical Sciences 2023 OA procedure engineering 0210 nano-technology Ternary operation Ternary droplet |
| Zdroj: | Proceedings of the National Academy of Sciences of the United States of America, 113(31), 8642-8647. National Academy of Sciences Proceedings of the National Academy of Sciences of the United States of America (PNAS), 113(31), 8642-8647. National Academy of Sciences Proceedings of the National Academy of Sciences of the United States of America |
| ISSN: | 0027-8424 |
| Popis: | Evaporating liquid droplets are omnipresent in nature and technology, such as in inkjet printing, coating, deposition of materials, medical diagnostics, agriculture, food industry, cosmetics, or spills of liquids. While the evaporation of pure liquids, liquids with dispersed particles, or even liquid mixtures has intensively been studied over the last two decades, the evaporation of ternary mixtures of liquids with different volatilities and mutual solubilities has not yet been explored. Here we show that the evaporation of such ternary mixtures can trigger a phase transition and the nucleation of microdroplets of one of the components of the mixture. As model system we pick a sessile Ouzo droplet (as known from daily life - a transparent mixture of water, ethanol, and anise oil) and reveal and theoretically explain its four life phases: In phase I, the spherical cap-shaped droplet remains transparent, while the more volatile ethanol is evaporating, preferentially at the rim of the drop due to the singularity there. This leads to a local ethanol concentration reduction and correspondingly to oil droplet nucleation there. This is the beginning of phase II, in which oil microdroplets quickly nucleate in the whole drop, leading to its milky color which typifies the so-called 'Ouzo-effect'. Once all ethanol has evaporated, the drop, which now has a characteristic non-spherical-cap shape, has become clear again, with a water drop sitting on an oil-ring (phase III), finalizing the phase inversion. Finally, in phase IV, also all water has evaporated, leaving behind a tiny spherical cap-shaped oil drop. 40 pages, 12 figures |
| Databáze: | OpenAIRE |
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