Marcus, Julien and Touraud, Didier and Kunz, Werner (2013) Formulation and stability of a soap microemulsion and the apparent pK(A) herein. JOURNAL OF COLLOID AND INTERFACE SCIENCE, 407. pp. 382-389. ISSN 0021-9797,
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The influence of composition, and added salts and polyols on the stability of an oil-in-water microemulsion formulation and on the apparent pK(A) (apK(A)) of the used oleate surfactant is investigated. High temperature favours a decrease of the apK(A) and leads to the formation of more hydrated micelles. The apK(A) decreases also when the percentage of ethanol increases. Citronellol molecules do not significantly influence the apK(A) at concentrations between 0% and 2% w/w. By contrast, with increasing limonene concentration, the apK(A) increases. It was observed that anions of sodium salts destabilize the microemulsion and high temperatures are needed to recover it. By increasing the concentration of NaCl, a slight increase of the apK(A) is observed, which can be associated with a non-specific, electrostatic (Debye-Huckel) effect. Cations of chloride salts have different effects depending on their ability to exchange with Na+ near the carboxylate group. Li+, Na+ and K+ have apparently a salting-out effect. Tetramethylammonium chloride and choline chloride have salting-in effects until respectively 0.6 and 0.4 mol kg(-1) The associations of sorbitol or glycerol with ethanol lead to a salting-in effect and to a decrease of the apK(A) of Na-Oleate. (C) 2013 Elsevier Inc. All rights reserved.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | PHASE-EQUILIBRIA; WATER; SOLUBILIZATION; SURFACTANT; SODIUM; SYSTEM; AGGREGATION; POTASSIUM; MICELLE; OLEATE; Hofmeister; Microemulsion; Sodium oleate; pK(A) |
| 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. Werner Kunz |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 31 Mar 2020 11:19 |
| Last Modified: | 31 Mar 2020 11:19 |
| URI: | https://pred.uni-regensburg.de/id/eprint/16007 |
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