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Evaporation of droplets of surfactant solutions

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journal contribution
posted on 14.07.2017 by Sergey Semenov, Anna Trybala, Hezekiah Agogo, Nina Kovalchuk, Francisco Ortega, Ramon Rubio, Victor Starov, M.G. Velarde
The simultaneous spreading and evaporation of droplets of aqueous trisiloxane (super-spreader) solutions onto a hydrophobic substrate has been studied both experimentally, using a video-microscopy technique, and theoretically. The experiments have been carried out over a wide range of surfactant concentration, temperature and relative humidity. Similar to pure liquids, four different stages have been observed: the initial one corresponds to spreading till the contact angle, , reaches the value of the static advancing contact angle, θad. Duration of this stage is rather short and the evaporation during this stage can be neglected. The evaporation is essential during next three stages. The next stage after the spreading, which is referred to below as the first stage, takes place at constant perimeter and ends when  reaches the static receding contact angle, θr. During the next, second stage, the perimeter decreases at constant contact angle =θr for surfactant concentration above critical wetting concentration (CWC). The static receding contact angle decreases during the second stage for concentrations below CWC because the concentration increases due to the evaporation. During the final stage both the perimeter and the contact angle decrease till the drop disappears. Below we consider only the longest stages one and two. The developed theory predicts universal curves for the contact angle dependency on time during the first stage, and for the droplet perimeter on time during the second stage. A very good agreement between theory and experimental data has been found for the first stage of evaporation, and for the second stage for concentrations above CWC, however, some deviations were found for concentrations below CWC.

History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering

Department

  • Chemical Engineering

Published in

Langmuir

Volume

29

Issue

32

Pages

10028 - 10036

Citation

SEMENOV, S. ... et al., 2013. Evaporation of droplets of surfactant solutions. Langmuir, 29(32), pp. 10028-10036.

Publisher

© American Chemical Society (ACS)

Version

AM (Accepted Manuscript)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Publication date

2013

Notes

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Langmuir, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://dx.doi.org/10.1021/la401578v

ISSN

0743-7463

eISSN

1520-5827

Language

en

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