Microemulsion formation
Microemulsions, which are transparent, fluid systems of high stability, were previously thought to be thermodynamically stable systems, requiring negative interfacial tensions for their formation. To determine if this was a correct hypothesis, microemulsions were prepared and studied by various techniques. Measurement of interfacial tension (..gamma../sub i/) as a function of time showed that when a short chain alcohol is injected into one phase of an oil/water system, the ..gamma../sub i/ will be reduced below its equilibrium value for a short period of time. If an interfacial film of surfactant is present, ..gamma../sub i/ can be reduced to zero for a period of time depending on the rate of transport of the alcohol away from the oil/water interface. Redistribution of the cosurfactant was shown to be a necessary process for the formation of microemulsions. The effects of the surfactant and solvent type were studied to determine the effect of these factors on microemulsion formation. Increasing the chain length of the surfactant was seen to decrease the requirement for a particular cosurfactant up to a given number of carbon atoms. Beyond that point, no microemulsions could be formed.
- OSTI ID:
- 6878702
- Country of Publication:
- United States
- Language:
- English
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