Effect of the macrobicyclic ligand Kryptofix 222 on AOT/water/cyclohexane microemulsions

Aerosol OT (AOT) exhibits a pronounced tendency toward reverse curvature, forming water in oil (w/o) droplets in the L{sub 2} region of the phase diagram in the three-component AOT/water/cyclohexane system. AOT's sodium counterion can be complexed by the addition of the macrobicyclic ligand 4,7...

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Bibliographic Details
Published in:Journal of physical chemistry (1952) 1991-10, Vol.95 (22), p.9013-9019
Main Authors: Leser, Martin E, Kooijman, Martin, Pollitte, Jonathan, Magid, Linda J
Format: Article
Language:English
Subjects:
02 PETROLEUM
020300 - Petroleum- Drilling & Production
400201 - Chemical & Physicochemical Properties
AEROSOLS
ALKANES
Chemistry
Colloidal state and disperse state
COLLOIDS
CYCLOALKANES
CYCLOHEXANE
DISPERSIONS
DROPLETS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
EMULSIONS
Emulsions. Microemulsions. Foams
Exact sciences and technology
FOURIER ANALYSIS
General and physical chemistry
HYDROCARBONS
HYDROGEN COMPOUNDS
INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY
LIGANDS
MAGNETIC RESONANCE
MICROEMULSIONS
NUCLEAR MAGNETIC RESONANCE
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PARTICLES
PHYSICAL PROPERTIES
RESONANCE
SOLS
VISCOSITY
WATER
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Summary:Aerosol OT (AOT) exhibits a pronounced tendency toward reverse curvature, forming water in oil (w/o) droplets in the L{sub 2} region of the phase diagram in the three-component AOT/water/cyclohexane system. AOT's sodium counterion can be complexed by the addition of the macrobicyclic ligand 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo(8.8.8)hexacosane (Kryptofix 222), which leads to significant changes in the phase behavior of the ternary microemulsion system. This contribution focuses on the structural changes occurring in the L{sub 2} phase upon addition of 25 mol % Kryptofix 222 with respect to AOT. The combination of static SANS, QELS, conductivity, viscosity, and PGSE FTNMR measurements lead to the following conclusions: (1) the droplet morphology is maintained; (2) a significant increase in the droplet-droplet attractions is observed; (3) the aggregates decrease in size at constant w{sub o}. The appearance of a critical point in the oil-rich corner of the pseudoternary phase diagram, where the surfactant system separated into dense and dilute microemulsion phases, confirmed the existence of strong interdroplet attractions. The AOT/25 mol % Kr222/water/cyclohexane microemulsion system resembles the AOT/water/decane droplet system in this respect.
ISSN:0022-3654
1541-5740
DOI:10.1021/j100175a107