ANSTO Publications Online >
Journal Publications >
Journal Articles >

Please use this identifier to cite or link to this item: http://apo.ansto.gov.au/dspace/handle/10238/1891

Title: Structure of high internal phase aqueous-in-oil emulsions and related inverse micelle solutions, 4 - surfactant mixtures.
Authors: Reynolds, PA
Gilbert, EP
Henderson, MJ
White, JW
Keywords: Surfactants
Aqueous Solutions
Emulsions
Small Angle Scattering
Oils
Molecular Weight
Issue Date: 10-Sep-2009
Publisher: American Chemical Society
Citation: Reynolds, P. A., Gilbert, E. P., Henderson, M. J., & White, J. W. (2009). Structure of high internal phase aqueous-in-oil emulsions and related inverse micelle solutions, 4 - surfactant mixtures. Journal of Physical Chemistry B, 113(36), 12243-12256.
Abstract: The effects of combinations of surfactants on the structure and stability of high internal phase water-in-hexadecane and saturated ammonium nitrate-in-hexadecane oil-based emulsions and oil-based inverse micellar solutions are reported, The combinations were 750, 1200, and 1700 molecular weight monodisperse and 450 and 1000 molecular weight polydisperse polyisobutylene acid amides, and sorbitan monooleate. The samples made from mixtures have qualitatively similar nanostructures to emulsions made from single surfactants. Again, for the emulsions, micrometer-scale aqueous droplets are dispersed in a continuous oil phase, which contains inverse spherical micelles composed of surfactant, hexadecane, and water. In quantitative terms, lower average surfactant molecular weight, lower ammonium nitrate content, and lower surfactant content increased the swelling of micelles, their water content, and the tendency of the emulsion to be unstable and form a sponge phase. This instability also allows micelle plasticity such that their geometry and content in mixed surfactant systems are not simply predictable by interpolation from single surfactant systems. An example was found of a mixed micelle 3 times larger than either single component micelle. The observed behavior suggests that mixing surfactant molecules of very different molecular weights destabilizes the emulsions, while mixing surfactants close in molecular weight has the opposite effect. The synergistic effects of surfactant molecular weight polydispersity and binary mixing are most marked for 1:1 molecular mixtures of surfactant. © 2009, American Chemical Society
URI: http://dx.doi.org/10.1021/jp903475z
http://apo.ansto.gov.au/dspace/handle/10238/1891
ISSN: 1520-6106
Appears in Collections:Journal Articles

Files in This Item:

There are no files associated with this item.

Items in APO are protected by copyright, with all rights reserved, unless otherwise indicated.

 

Valid XHTML 1.0! DSpace Software Copyright © 2002-2010  Duraspace - Feedback