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Structure of high internal phase aqueous-in-oil emulsions and related inverse Micelle solutions. 4. Surfactant mixtures

Reynolds, Philip; Gilbert, Elliot P; Henderson, Mark; White, John

Description

The effects of combinations of surfactants on the structure and stability of high internal phase water-inhexadecane 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...[Show more]

dc.contributor.authorReynolds, Philip
dc.contributor.authorGilbert, Elliot P
dc.contributor.authorHenderson, Mark
dc.contributor.authorWhite, John
dc.date.accessioned2015-12-10T22:40:12Z
dc.identifier.issn1520-6106
dc.identifier.urihttp://hdl.handle.net/1885/57381
dc.description.abstractThe effects of combinations of surfactants on the structure and stability of high internal phase water-inhexadecane 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.
dc.publisherAmerican Chemical Society
dc.sourceJournal of Physical Chemistry B
dc.subjectKeywords: Ammonium nitrate; Aqueous droplets; Binary mixing; Close-in; Hexadecane; Internal phase; Inverse micelles; Lower average; Micellar solution; Micrometer-scale; Mixed micelles; Mixed surfactant systems; Molecular mixtures; Monodisperse; Oil emulsions; Oil p
dc.titleStructure of high internal phase aqueous-in-oil emulsions and related inverse Micelle solutions. 4. Surfactant mixtures
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume113
dc.date.issued2009
local.identifier.absfor030603 - Colloid and Surface Chemistry
local.identifier.ariespublicationu4217927xPUB398
local.type.statusPublished Version
local.contributor.affiliationReynolds, Philip, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationGilbert, Elliot P, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationHenderson, Mark, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationWhite, John, College of Physical and Mathematical Sciences, ANU
local.description.embargo2037-12-31
local.bibliographicCitation.issue36
local.bibliographicCitation.startpage12243
local.bibliographicCitation.lastpage12256
local.identifier.doi10.1021/jp903475z
dc.date.updated2016-02-24T10:43:02Z
local.identifier.scopusID2-s2.0-69949143094
local.identifier.thomsonID000269655300011
CollectionsANU Research Publications

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