Stability of bubbles in wax-based oleofoams: decoupling the effects of bulk oleogel rheology and interfacial rheology
File(s)Saha2020_Article_StabilityOfBubblesInWax-basedO.pdf (2.38 MB)
Published version
Author(s)
Saha, saikat
Saint-Michel, brice
Leynes, Vaughn
Binks, Bernard P
Garbin, Valeria
Type
Journal Article
Abstract
Oleofoams are dispersions of gas bubbles in a continuous oil phase and can be stabilized by crystals of fatty acids or waxes adsorbing at the oil-air interface. Because excess crystals in the continuous phase form an oleogel, an effect of the bulk rheology of the continuous phase is also expected. Here, we evaluate the contributions of bulk and interfacial rheology below and above the melting point of a wax forming an oleogel in sunflower oil. We study the dissolution behaviour of single bubbles using microscopy on a temperature-controlled stage. We compare the behaviour of a bubble embedded in an oleofoam, which owes its stability to both bulk and interfacial rheology, to that of a bubble extracted from the oleofoam and resuspended in oil, for which the interfacial dilatational rheology alone provides stability. We find that below the melting point of the wax, bubbles in the oleofoam are stable whereas bubbles that are only coated with wax crystals dissolve. Both systems dissolve when heated above the melting point of the wax. These findings are rationalized through independent bulk rheological measurements of the oleogel at different temperatures, as well as measurements of the dilatational rheological properties of a wax-coated oil-air interface.
Date Issued
2020-04
Date Acceptance
2020-01-29
Citation
Rheologica Acta: an international journal of rheology, 2020, 59, pp.255-266
ISSN
0035-4511
Publisher
Springer Verlag
Start Page
255
End Page
266
Journal / Book Title
Rheologica Acta: an international journal of rheology
Volume
59
Copyright Statement
© 2020 The Author(s).This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
Sponsor
Commission of the European Communities
Identifier
https://link.springer.com/article/10.1007%2Fs00397-020-01192-x
Grant Number
639221
Subjects
Science & Technology
Technology
Mechanics
Oleofoam
Oleogel
Bubble dissolution
Interfacial rheology
CRUDE OILS
COATED BUBBLES
DISSOLUTION
FOAMS
STABILIZATION
PARTICLES
BEHAVIOR
TENSION
SURFACE
SHAPE
Polymers
0904 Chemical Engineering
0913 Mechanical Engineering
0915 Interdisciplinary Engineering
Publication Status
Published
Date Publish Online
2020-03-09