Determination of microemulsion phase continuity and drop size by ultracentrifugation
It is noted that microemulsions play an important role in achieving ultralow interfacial tensions which are essential to the success of certain processes being developed for enhanced petroleum recovery. The ultracentrifuge has confirmed the existence of oil-in-water microemulsions at low salinities and water-in-oil microemulsions at high salinities in systems containing an anionic surfactant and an alcohol cosurfactant. Drop sizes calculated from sedimentation rate data are reasonable and vary with salinity and surfactant chain length in a manner which is consistent with solubilization data. The ultracentrifuge results also show that the surfactant phase is water-continuous in the lower salinity portion of its range of existence and oil-continuous in the higher salinity portion. These results confirm that the surfactant phase forms as a result of phase separation in microemulsions or micellar solutions, as was previously proposed. Between its oil-in-water and water-in-oil regions, the surfactant phase shows two peaks when subjected to ultracentrifugation, one characteristic of oil-continuous behavior and one characteristic of water-continuous behavior. Possibly it consists of a mixture of the two types of microemulsions. The observed variation of drop size with salinity can be explained in terms of changes in interaction between surfactant ions due to variation in charge screening with salinity.
- Research Organization:
- Carnegie-Mellon Univ., Pittsburgh, PA
- OSTI ID:
- 6389876
- Report Number(s):
- CONF-780305-P3
- Journal Information:
- Prepr., Div. Pet. Chem., Am. Chem. Soc.; (United States), Journal Name: Prepr., Div. Pet. Chem., Am. Chem. Soc.; (United States) Vol. 23:3; ISSN ACPCA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
020300 -- Petroleum-- Drilling & Production
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
CENTRIFUGATION
COLLOIDS
DISPERSIONS
DROPLETS
EMULSIONS
HYDROGEN COMPOUNDS
MICROEMULSIONS
MIXTURES
OILS
ORGANIC COMPOUNDS
OTHER ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PARTICLES
PHASE STUDIES
SALINITY
SEPARATION PROCESSES
SURFACTANTS
WATER