Spreading and retraction dynamics of sessile evaporating droplets comprising volatile binary mixtures
Author(s)
Type
Journal Article
Abstract
The dynamics of thin volatile droplets comprising of binary mixtures deposited on a heated substrate are investigated. Using lubrication theory, we develop a novel one-sided model to predict the spreading and retraction of an evaporating sessile axisymmetric droplet formed of a volatile binary mixture on a substrate with high wettability. A thin droplet with a moving contact line is considered, taking into account the variation of liquid properties with concentration as well as the effects of inertia. The parameter space is explored and the resultant effects on wetting and evaporation are evaluated. Increasing solutal Marangoni stress enhances spreading rates in all cases, approaching those of superspreading liquids. To validate our model, experiments are conducted with binary ethanol–water droplets spreading on hydrophilic glass slides heated from below. The spreading rate is quantified, revealing that preferential evaporation of the more volatile component (ethanol) at the contact line drives superspreading, leading in some cases to a contact line instability. Good qualitative agreement is found between our model and experiments, with quantitative agreement being achieved in terms of spreading rate.
Date Issued
2021-01-25
Date Acceptance
2020-09-28
Citation
Journal of Fluid Mechanics, 2021, 907 (A22), pp.1-46
ISSN
0022-1120
Publisher
Cambridge University Press
Start Page
1
End Page
46
Journal / Book Title
Journal of Fluid Mechanics
Volume
907
Issue
A22
Copyright Statement
© The Author(s), 2020. Published by Cambridge University Press. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.
License URL
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000591615200001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Technology
Physical Sciences
Mechanics
Physics, Fluids & Plasmas
Physics
Marangoni convection
drops
thermocapillarity
HYDROTHERMAL WAVES
LIQUID DROPLETS
CONTACT-ANGLE
DROPS
PATTERNS
WATER
FLOW
TEMPERATURE
VAPOR
Publication Status
Published
Article Number
PII S002211202000840X
Date Publish Online
2020-11-23