Titlebar

Bibliografische Daten exportieren
Literatur vom gleichen Autor
plus auf ERef Bayreuth
plus bei Google Scholar

 

Coalescence and Noncoalescence of Sessile Drops : Impact of Surface Forces

Titelangaben

Karpitschka, Stefan ; Hanske, Christoph ; Fery, Andreas ; Riegler, Hans:
Coalescence and Noncoalescence of Sessile Drops : Impact of Surface Forces.
In: Langmuir. Bd. 30 (Juni 2014) Heft 23 . - S. 6826-6830.
ISSN 1520-5827
DOI: https://doi.org/10.1021/la500459v

Volltext

Link zum Volltext (externe URL): Volltext

Abstract

Due to capillarity, sessile droplets of identical liquids will instantaneously fuse when they come in contact at their three-phase lines. However, with drops of different, completely miscible liquids, instantaneous coalescence can be suppressed. Instead, the drops remain in a state of noncoalescence for some time, with the two drop bodies connected only by a thin neck. The reason for this noncoalescence is the surface tension difference, Δγ, between the liquids. If Δγ is sufficiently large, then it induces a sufficiently strong Marangoni flow, which keeps the main drop bodies temporarily separated. Studies with spreading drops have revealed that the boundary between instantaneous coalescence and noncoalescence is sharp (Karpitschka, S.; Riegler, H. J. Fluid. Mech. 2014, 743, R1). The boundary is a function of two parameters only: Δγ and Θ̅a, the arithmetic mean of the contact angles in the moment of drop−drop contact. It appears plausible that surface forces (the disjoining pressure) could also influence the coalescence behavior. However, in experiments with spreading drops, surface forces always promote coalescence and their influence might be obscured. Therefore, we present here coalescence experiments with partially wetting liquids and compare the results to the spreading case. We adjust different equilibrium contact angles (i.e., different surface forces) with different substrate surface coatings. As for spreading drops, we observe a sharp boundary between regimes of coalescence and noncoalescence. The boundary follows the same power law relation for both partially and completely wetting cases. Therefore, we conclude that surface forces have no significant, explicit influence on the coalescence behavior of sessile drops from different miscible liquids.

Weitere Angaben

Publikationsform: Artikel in einer Zeitschrift
Begutachteter Beitrag: Ja
Institutionen der Universität: Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften
Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie
Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie > Ehemalige Professoren > Lehrstuhl Physikalische Chemie II - Univ.-Prof. Dr. Andreas Fery
Forschungseinrichtungen > Sonderforschungsbereiche, Forschergruppen > SFB 840 Von partikulären Nanosystemen zur Mesotechnologie
Fakultäten
Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie > Lehrstuhl Physikalische Chemie II
Forschungseinrichtungen
Forschungseinrichtungen > Sonderforschungsbereiche, Forschergruppen
Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie > Ehemalige Professoren
Titel an der UBT entstanden: Ja
Themengebiete aus DDC: 500 Naturwissenschaften und Mathematik > 500 Naturwissenschaften
500 Naturwissenschaften und Mathematik > 530 Physik
500 Naturwissenschaften und Mathematik > 540 Chemie
Eingestellt am: 05 Dec 2014 09:49
Letzte Änderung: 05 Dec 2014 09:49
URI: https://eref.uni-bayreuth.de/id/eprint/3925