Lima, Filipe S. and Cuccovia, Iolanda M. and Horinek, Dominik and Amaral, Lia Q. and Riske, Karin A. and Schreier, Shirley and Salinas, Roberto K. and Bastos, Erick L. and Pires, Paulo A. R. and Bozelli, Jose Carlos and Favaro, Denize C. and Rodrigues, Ana Clara B. and Dias, Luis Gustavo and El Seoud, Omar A. and Chaimovich, Hernan (2013) Effect of Counterions on the Shape, Hydration, and Degree of Order at the Interface of Cationic Micelles: The Triflate Case. LANGMUIR, 29 (13). pp. 4193-4203. ISSN 0743-7463,
Full text not available from this repository. (Request a copy)Abstract
Specific ion effects in surfactant solutions affect the properties of micelles. Dodecyltrimethylammonium chloride (DTAC), bromide (DTAB), and methanesulfonate (DTAMs) micelles are typically spherical, but some organic anions can induce shape or phase transitions in DTA(+) micelles. Above a defined concentration, sodium triflate (NaTf induces a phase separation in dodecyltrimethylammonium triflate (DTATf micelles, a phenomenon rarely observed in cationic micelles. This unexpected behavior of the DTATf/NaTf system suggests that DTATf aggregates have unusual properties. The structural properties of DTATf micelles were analyzed by time-resolved fluorescence quenching, small-angle X-ray scattering, nuclear magnetic resonance, and electron paramagnetic resonance and compared with those of DTAC, DTAB, and DTAMs micelles. Compared to the other micelle types, the DTATf micelles had a higher average number of monomers per aggregate, an uncommon disk-like shape, smaller interfacial hydration, and restricted monomer chain mobility. Molecular dynamic simulations supported these observations. Even small water-soluble salts can profoundly affect micellar properties; our data demonstrate that the -CF3 group in Tf- was directly responsible for the observed shape changes by decreasing interfacial hydration and increasing the degree of order of the surfactant chains in the DTATf micelles.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | ANGLE NEUTRON-SCATTERING; DODECYL-SULFATE MICELLES; ELECTRON-SPIN RESONANCE; AQUEOUS NABR SOLUTIONS; TO-ROD TRANSITION; IONIC SURFACTANTS; GEMINI SURFACTANTS; DODECYLTRIMETHYLAMMONIUM CHLORIDE; AIR/WATER INTERFACE; MAGNETIC-RELAXATION; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Chair of Chemistry VI - Physical Chemistry (Solution Chemistry) > Prof. Dr. Dominik Horinek |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 17 Apr 2020 06:58 |
| Last Modified: | 17 Apr 2020 06:58 |
| URI: | https://pred.uni-regensburg.de/id/eprint/16842 |
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