Elasticity of foam bubbles measured by profile analysis tensiometry

Karakashev, SI, Tsekov, R, Manev, ED and Nguyen, AV (2010) Elasticity of foam bubbles measured by profile analysis tensiometry. Colloids And Surfaces A-physicochemical And Engineering Aspects, 369 1-3: 136-140. doi:10.1016/j.colsurfa.2010.08.008

Author Karakashev, SI
Tsekov, R
Manev, ED
Nguyen, AV
Title Elasticity of foam bubbles measured by profile analysis tensiometry
Journal name Colloids And Surfaces A-physicochemical And Engineering Aspects   Check publisher's open access policy
ISSN 0927-7757
Publication date 2010-10
Sub-type Article (original research)
DOI 10.1016/j.colsurfa.2010.08.008
Volume 369
Issue 1-3
Start page 136
End page 140
Total pages 5
Place of publication Amsterdam, Netherlands
Publisher Elsevier BV
Collection year 2011
Language eng
Formatted abstract
Elastic modulus of foam bubbles, stabilized with tetraethylene glycol octyl ether (C8E4) and 1×10−5M NaCl, was determined by cyclic expansion and shrinking of foam bubbles with frequency of 0.1 Hz and volumetric amplitude of 2mm3. The film tension was monitored by a commercial profile analysis tensiometer (Sinterface Technologies, GmbH). The elastic moduli of foam bubbles were obtained as a function of surfactant concentration in the range of 2×10−3–1×10−2 M. The theory of Lucassen and van den Tempel [1] for the elastic modulus of a single liquid/air interface at a given frequency was employed. In the theoretical analysis the bulk diffusion coefficient of surfactant molecules was considered as a unknown model parameter which was obtained by matching the theory with the experimental data. Hence, the dependence of the bulk diffusion coefficient of C8E4 molecules upon the C8E4 concentration was obtained. The diffusion coefficient reached a maximum at 5×10−3M C8E4 (D= 8.5×10−11m2/s). In the experimental surfactant concentration range (2×10−3–1×10−2 M, CMC= 7.5×10−3 M) the foam bubbles were relatively dry, with visible interferometric fringes corresponding to thin films stabilized by repulsion of the electrostatic disjoining pressure. Hence, the overall dynamics of periodical expansion and shrinking of the foam bubbles occurred within the thin film state.
© 2010 Elsevier B.V. All rights reserved.
Keyword Elastic modulus
Gibbs elasticity
Foam films
Soap bubble
Adsorption frequency
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Chemical Engineering Publications
Official 2011 Collection
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Citation counts: TR Web of Science Citation Count  Cited 8 times in Thomson Reuters Web of Science Article | Citations
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Created: Sun, 07 Nov 2010, 00:14:29 EST