Investigation of micelles, microemulsions, and phospholipid bilayers with the pyridinium N-phenolbetaine et(30), a polarity probe for aqueous interfaces
The phenolbetaine et(30), a well-known internal probe of solvent polarity, is used to characterize the polarity of its environment in micelles, microemulsions, and phospholipid bilayers. The probe molecule, invariably solubilized in the aqueous interface, senses changes in polarity brought about by salt addition and variation of surfactant chain length and concentration, counterion, and temperature. These changes in polarity can be correlated with variations in the micellar aggregation number, signifying that the immediate probe surroundings become less polar when the micelle increases in size. With sodium dodecyl sulfate micelles a discontinuity in the variation of the et(30) value with the aggregation number is observed at 0.45 mole added NaCl, where the shape of the micelles has been reported to undergo a sphere-to-rod transition. The microemulsions behave as swollen micelles. The lowest polarity, comparable to that of 1-butanol, is observed for the phospholipid bilayers. 49 references.
- OSTI ID:
- 5236815
- Journal Information:
- J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 85:18; ISSN JPCHA
- Country of Publication:
- United States
- Language:
- English
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ALKALI METAL COMPOUNDS
CHLORIDES
CHLORINE COMPOUNDS
COLLOIDS
CRYSTAL STRUCTURE
DISPERSIONS
DISPLACEMENT FLUIDS
EMULSIONS
ESTERS
FLUIDS
HALIDES
HALOGEN COMPOUNDS
INTERFACES
LIPIDS
MICELLAR SYSTEMS
MICROEMULSIONS
MICROSTRUCTURE
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
OXYGEN COMPOUNDS
PHOSPHOLIPIDS
POLARIZATION
PROBES
SODIUM CHLORIDES
SODIUM COMPOUNDS
SODIUM SULFATES
SULFATES
SULFUR COMPOUNDS