Nano- and microstructure of air/oil/water interfaces
We report the creation of air/oil/water interfaces with variable-thickness oil films using polyisobutylene-based (PIB) surfactants cospread with long-chain paraffinic alkanes on clean water surfaces. The resultant stable oil layers are readily measurable with simple surface techniques, exhibit physi...
| Publié dans: | Langmuir : the ACS journal of surfaces and colloids. - 1991. - 25(2009), 7 vom: 07. Apr., Seite 4065-9 |
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| Auteur principal: | |
| Autres auteurs: | , , |
| Format: | Article |
| Langue: | English |
| Publié: |
2009
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| Accès à la collection: | Langmuir : the ACS journal of surfaces and colloids |
| Sujets: | Journal Article Research Support, Non-U.S. Gov't Alkanes Oils Surface-Active Agents Water 059QF0KO0R |
| Résumé: | We report the creation of air/oil/water interfaces with variable-thickness oil films using polyisobutylene-based (PIB) surfactants cospread with long-chain paraffinic alkanes on clean water surfaces. The resultant stable oil layers are readily measurable with simple surface techniques, exhibit physical densities the same as expected for bulk oils, and are up to approximately 100 A thick above the water surface as determined using X-ray reflectometry. This provides a ready system for studying the competition of surfactants at the oil/water interface. Results from the competition of a nonionic polyamide surfactant or an anionic sodium dodecyl sulfate with the PIB surfactant are reported. However, this smooth oil layer does not account for the total volume of spread oil nor is the increase in thickness proportional to the film compression. Brewster angle microscopy (BAM) reveals surfactant and oil structures on the scale of 1 to 10 microm at the interface. At low surface pressure (pi < 24 mN m(-1)) large, approximately 10 microm inhomogeneities are observed. Beyond a phase transition observed at pi approximately = 24 mN m(-1), a structure with a spongy appearance and a microscale texture develops. These structures have implications for understanding the microstructure at the oil/water interface in emulsions |
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| Description: | Date Completed 22.09.2009 Date Revised 27.10.2019 published: Print Citation Status MEDLINE |
| ISSN: | 1520-5827 |