Medos, Ziga and Plechkova, Natalia and Friesen, Sergej and Buchner, Richard and Bester-Rogac, Marija (2019) Insight into the Hydration of Cationic Surfactants: A Thermodynamic and Dielectric Study of Functionalized Quaternary Ammonium Chlorides. LANGMUIR, 35 (10). pp. 3759-3772. ISSN 0743-7463,
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Hydrophobic interactions are one of the main thermodynamic driving forces in self-assembly, folding, and association processes. To understand the dehydration-driven solvent exposure of hydrophobic surfaces, the micellization of functionalized decyldimethylammonium chlorides, XC10Me2N+Cl-, with a polar functional group, X = C2OH, C2OMe, C2OC2OMe, C2OOEt, together with the "reference" compound decyltrimethylammonium chloride, C10Me3N+Cl-, was investigated in aqueous solution by density measurements, isothermal titration calorimetry (ITC), and dielectric relaxation spectroscopy (DRS). From the density data, the apparent molar volumes of monomers and micelles were estimated, whereas the ITC data were analyzed with the help of a model equation, yielding the thermodynamic parameters and aggregation number. From the DRS spectra, effective hydration numbers of the free monomers and micelles were deduced. The comprehensive analysis of the obtained results shows that the thermodynamics of micellization are strongly affected by the nature of the functional group. Surprisingly, the hydration of micelles formed by surfactant cations with a single alkyl chain on quaternary ammonium is approximately the same, regardless of the alkyl chain length or functionalization of the headgroup. However, notable differences were found for the free monomers where increasing polarity lowers the effective hydration number.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | ISOTHERMAL TITRATION CALORIMETRY; HEAT-CAPACITY CHANGES; MICELLE FORMATION; AQUEOUS-SOLUTION; ALKYLTRIMETHYLAMMONIUM CHLORIDES; RELAXATION SPECTROSCOPY; AGGREGATION BEHAVIOR; IONIC LIQUIDS; LOW-FREQUENCY; MICELLIZATION; |
| 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) > PD Dr. Richard Buchner |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 21 Apr 2020 04:47 |
| Last Modified: | 21 Apr 2020 04:47 |
| URI: | https://pred.uni-regensburg.de/id/eprint/27367 |
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