Rapid Spreading of a Droplet on a Thin Soap Film.

TitleRapid Spreading of a Droplet on a Thin Soap Film.
Publication TypeJournal Article
Year of Publication2019
AuthorsMotaghian, M, Shirsavar, R, Erfanifam, M, Sabouhi, M, van der Linden, E, Stone, HA, Bonn, D, Habibi, M
JournalLangmuir
Volume35
Issue46
Pagination14855-14860
Date Published2019 Nov 19
ISSN1520-5827
Abstract

We study the spreading of a droplet of surfactant solution on a thin suspended soap film as a function of dynamic surface tension and volume of the droplet. Radial growth of the leading edge (R) shows power-law dependence on time with exponents ranging roughly from 0.1 to 1 for different surface tension differences (Δσ) between the film and the droplet. When the surface tension of the droplet is lower than the surface tension of the film (Δσ > 0), we observe rapid spreading of the droplet with Rtα, where α (0.4 < α < 1) is highly dependent on Δσ. Balance arguments assuming the spreading process is driven by Marangoni stresses versus inertial stresses yield α = 2/3. When the surface tension difference does not favor spreading (Δσ < 0), spreading still occurs but is slow with 0.1 < α < 0.2. This phenomenon could be used for stretching droplets in 2D and modifying thin suspended films.

DOI10.1021/acs.langmuir.9b02274
Alternate JournalLangmuir
PubMed ID31644302
PubMed Central IDPMC6868707