ISSN:
0001-1541
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Microemulsions, which are optically transparent oil-water dispersions, were spontaneously produced upon mixing hexadecane, hexanol, potassium oleate, and water in specific proportions. The drop-volume measurements of hexadecane-water interface in the presence of hexanol or potassium oleate revealed that these surfactants decrease the interracial tension of the hexadecane/water interface. It is proposed that the interaction between these two emulsifiers at the oil-water interface causes spontaneous negative interfaical tension resulting in interfacial instability and the formation of microemulsions.As the amount of water is increased, the microemulsion exhibits a clear to turbid to clear transition. Unlike the clear regions, the turbid region possesses birefringence. The development of birefringence is also accompanied by a sharp decrease in electrical resistance. High-resolution (220 Mc) nuclear magnetic resonance data suggest that water exists in two distinct environments or structures in the birefringent region. The electrical, birefringence, and nuclear magnetic resonance data agree with the proposed mechanism of phase-inversion of microemulsions, which can be described as water spheres to water cylinders to water lamellae to a continuous water phase. The spontaneous formation of such structures (for example, water cylinders and lamellae) presumably depends upon the phase-volume ratio and the interfacial tension at the oil-water interface.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/aic.690180605
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