Denk, Patrick and Reigl, Selina and Roedig, Bastian and Sztucki, Michael and Prevost, Sylvain and Zemb, Thomas and Kunz, Werner (2025) Biliquid oil-in-water nanofoams and spontaneous emulsification obtained with a surfactant resistant to curvature changes. JOURNAL OF COLLOID AND INTERFACE SCIENCE, 684Pt2. pp. 105-121. ISSN 0021-9797, 1095-7103
Full text not available from this repository. (Request a copy)Abstract
Hypothesis: Due to its huge polar headgroup, octaoxyethylene octyl ether carboxylic acid (C8E8CH2COOH Akypo LF2TM) is supposed not to be able to change its curvature sufficiently to form bicontinuous micro emulsions. Instead, upon adding an oil to the binary water - surfactant system, excess oil could be squeezed out or a biliquid foam could form. Experiments: An auto-dilution setup was used to record small-angle X-ray scattering data along six dilution lines in the newly established phase diagram of the ternary system 2-ethylhexanol - C8E8CH2COOH - water. Results: Evaluation of the data in combination with the recorded phase diagram revealed that the ternary microemulsions with a slightly amphiphilic oil indeed do not show a classical structural inversion via a bicontinuous structure with increasing oil content, but instead the sequence: O/W micelles - O/W biliquid nanofoam molecular co-solubilization in the oil phase. The biliquid nanofoam structure with 102-104 oil molecules enclosed by locally flat layers of interdigitated hydrated headgroups exists in the middle of the phase diagram. We may speculate that this phase can be used as a multitude of nanocontainers, e.g., for chemical reactions in an aqueous environment, but with negligible water chemical potential. In the vicinity of the critical point, spontaneous formation of stable mesoscale droplets (an "Onuki-like" structure, as known with antagonistic salts) is detected in a region showing a pronounced Tyndall effect.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | SMALL-ANGLE SCATTERING; X-RAY-SCATTERING; PHASE-EQUILIBRIA; MICROEMULSIONS; HYDRATION; MICROSTRUCTURE; MODEL; Nanofoam; Biliquid foam; Emulsification; Microemulsion; Small-angle scattering; Akypo LF2; Alkyl ether carboxylate; Nanoreactors |
| 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: | 18 Jun 2026 05:37 |
| Last Modified: | 18 Jun 2026 05:37 |
| URI: | https://pred.uni-regensburg.de/id/eprint/66640 |
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