Fluorescence probe studies of mixed micellar and lyotropic phases formed between an anionic bile salt and a cationic detergent
- Duke Univ., Durham, NC (United States)
Fluorescent probes, including pyrene, benzo[ghi]perylene (BgP), and perylene, were used to study organized media formed between the anionic trihydroxy bile salt sodium taurocholate (NaTC) and the cationic detergent octyltrimethylammonium bromide (CTAB), over a wide concentration range that includes micellar and lyotropic phases. Solutions of the individual amphiphiles were studied as well. The location of a probe in the mixed micelles was found to depend on the solubility and size of the probe. The microenvironment of pyrene is dominated by NaTC in the mixed micelles, whereas the larger and less soluble perylene and BgP probes interact more favorably with the hydrophobic tails of the CTAB molecules. The photophysical responses of the probes reflect their different locations, providing different perspectives on the transitions in micellar structure. Bromide counterion at the micellar surfaces was found to be an important factor in the photophysical responses, along with accessibility to bulk solution. A scheme for mixed micellization is proposed that extends from large excesses of one amphiphile to large excesses of the other, over a wide range of total amphiphile concentration. Interestingly, the lyotropic phases formed between NaTC and CTAB have high bulk viscosity, but the probe microenvironment is less viscous than in the mixed micellar phases. 43 refs., 9 figs., 2 tabs.
- DOE Contract Number:
- FG05-88ER13931
- OSTI ID:
- 5041572
- Journal Information:
- Journal of Physical Chemistry; (United States), Vol. 98:4; ISSN 0022-3654
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
59 BASIC BIOLOGICAL SCIENCES
BILE ACIDS
AGGLOMERATION
MICELLAR SYSTEMS
FLUORESCENCE SPECTROSCOPY
DETERGENTS
PERYLENE
PROBES
PYRENE
SALTS
SOLUTIONS
VISCOSITY
ADDITIVES
AROMATICS
CARBOXYLIC ACIDS
CONDENSED AROMATICS
DISPERSIONS
EMISSION SPECTROSCOPY
EMULSIFIERS
HYDROCARBONS
HYDROXY COMPOUNDS
MIXTURES
ORGANIC ACIDS
ORGANIC COMPOUNDS
SPECTROSCOPY
STEROIDS
STEROLS
SURFACTANTS
WETTING AGENTS
400201* - Chemical & Physicochemical Properties
550200 - Biochemistry