Dynamic light scattering from cetyltrimethylammonium bromide micelles: intermicellar interactions at low ionic strengths
Quasi-elastic light scattering measurements have been performed on aqueous solutions of CTAB (cetyltrimethylammonium bromide). Theoretic fits to the measured diffusion coefficients at low NaBr were obtained by using the generalized Stokes-Einstein equation expanded to first order in the surfactant concentration (including both thermodynamic and hydrodynamic terms), with a pair-interaction potential taken from Dlvo theory. Good fits are obtained at low NaBr concentrations by assuming a constant micellar radius for each temperature and assuming that the remaining parameters (aggregation number, fractional ionization, and Hamaker coefficient) are independent of temperature. This procedure yields an unambiguous value for the fractional ionization alpha for CTAB micelles: alpha = 0.22. The limits of validity of the theoretic fitting procedure (previously applied by Corti and Degiorgio to the system sodium n-dodecyl sulfate (SDS) + NaCl) are discussed. 65 references.
- OSTI ID:
- 5968180
- Journal Information:
- J. Phys. Chem.; (United States), Vol. 86:13
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
MICELLAR SYSTEMS
QUASI-ELASTIC SCATTERING
AQUEOUS SOLUTIONS
EMULSIONS
ENHANCED RECOVERY
LIGHT SCATTERING
MOLECULAR STRUCTURE
ORGANIC BROMINE COMPOUNDS
PARTICLE SIZE
PETROLEUM
PHASE STUDIES
SODIUM BROMIDES
SODIUM CHLORIDES
SODIUM SULFATES
SURFACTANTS
TESTING
VISCOSITY
WATERFLOODING
ALKALI METAL COMPOUNDS
BROMIDES
BROMINE COMPOUNDS
CHLORIDES
CHLORINE COMPOUNDS
COLLOIDS
DIRECT REACTIONS
DISPERSIONS
ENERGY SOURCES
FLUID INJECTION
FOSSIL FUELS
FUELS
HALIDES
HALOGEN COMPOUNDS
MIXTURES
NUCLEAR REACTIONS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXYGEN COMPOUNDS
QUASI-FREE REACTIONS
RECOVERY
SCATTERING
SIZE
SODIUM COMPOUNDS
SOLUTIONS
SULFATES
SULFUR COMPOUNDS
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