Formation and stability of foams stabilized by fine particles with similar size, contact angle and different shapes

Karakashev, Stoyan I., Ozdemir, Orhan, Hampton, Marc A. and Nguyen, Anh V. (2011). Formation and stability of foams stabilized by fine particles with similar size, contact angle and different shapes. In: Peter A. Kralchevsky and Nikolai Denkov, A collection of papers from the 8th EUFOAM Conference and the Meetings of COST Actions D43 and P21. 8th EUFOAM Conference/Meeting on COST Actions D43 and P21, Borovets, Bulgaria, (132-138). 13-16 July 2010. doi:10.1016/j.colsurfa.2010.09.023


Author Karakashev, Stoyan I.
Ozdemir, Orhan
Hampton, Marc A.
Nguyen, Anh V.
Title of paper Formation and stability of foams stabilized by fine particles with similar size, contact angle and different shapes
Conference name 8th EUFOAM Conference/Meeting on COST Actions D43 and P21
Conference location Borovets, Bulgaria
Conference dates 13-16 July 2010
Proceedings title A collection of papers from the 8th EUFOAM Conference and the Meetings of COST Actions D43 and P21   Check publisher's open access policy
Journal name Colloids and Surfaces A: Physicochemical and Engineering Aspects   Check publisher's open access policy
Place of Publication Amsterdam, Netherlands
Publisher Elsevier
Publication Year 2011
Sub-type Fully published paper
DOI 10.1016/j.colsurfa.2010.09.023
ISSN 0927-7757
1873-4359
Editor Peter A. Kralchevsky
Nikolai Denkov
Volume 382
Issue 1-3
Start page 132
End page 138
Total pages 7
Collection year 2012
Language eng
Formatted Abstract/Summary
Enhancement of foam formation and stability by solid particles has been attributed to particle hydrophobicity and size. In this article it is shown that particle shape is a significant factor affecting foam formation and stability. Silica (spherical) and sepiolite (fibrous) particles with diameter d90 = 38 μm, and contact angle of 66° and 60°, respectively, were used to form foams by stirring the particle suspensions in the presence of 1 × 10−4 M sodium dodecyl sulphate at 1000 rpm. Measurements of foam volume versus time and different particle concentrations (0, 0.01, 0.1, 1.0, 2.0 and 4.0% by weight) during the foam generation and decay show that the silica spherical particles did not affect the foamability significantly whereas the fibrous sepiolite particles substantially increased the foamability, reaching a maximum beyond 0.1 wt% particle concentration. Both micron silica spheres and sepiolite needles increased the rate of foam decay, reaching maximum at 0.1 wt% concentration. Overall, the lifetime of foams stabilized by sepiolite fibres was significantly longer than the lifetime of foams stabilized by silica spheres. It is hypothesised that the difference in the foam formation and stability is related to the contact between the particles. For example, two spheres can contact only at one point, while two fibres can entangle to increase contact area. Under such conditions, aggregates of fibrous particles can have a large amount of hydrated water, leading to increased suspension viscosity and the formation of an interfacial crosslink network to stabilize foams.
Keyword Foams stabilized by particles
Contact angle
Particle shape
Foamability
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Conference Paper
Collections: School of Chemical Engineering Publications
Official 2012 Collection
 
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