Adsorption of aromatic counterions at the surfactant/water interface : a neutron reflectivity study of hydroxybenzoate and chlorobenzoate counterions at the hexadecyl trimethylammonium surfactant/water interface
Specular neutron reflectivity has been used to investigate the adsorption of the aromatic counterions hydroxybenzoate and chlorobenzoate at the hexadecyl trimethylammonium bromide surfactant monolayer/water interface. The degree of counterion binding and the location of the counterions at the interf...
| Veröffentlicht in: | Langmuir : the ACS journal of surfaces and colloids. - 1992. - 20(2004), 19 vom: 14. Sept., Seite 8054-61 |
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| 1. Verfasser: | |
| Weitere Verfasser: | , , |
| Format: | Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2004
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| Zugriff auf das übergeordnete Werk: | Langmuir : the ACS journal of surfaces and colloids |
| Schlagworte: | Journal Article Research Support, Non-U.S. Gov't Cetrimonium Compounds Chlorobenzoates Hydroxybenzoates Surface-Active Agents Water 059QF0KO0R Cetrimonium Z7FF1XKL7A |
| Zusammenfassung: | Specular neutron reflectivity has been used to investigate the adsorption of the aromatic counterions hydroxybenzoate and chlorobenzoate at the hexadecyl trimethylammonium bromide surfactant monolayer/water interface. The degree of counterion binding and the location of the counterions at the interface are shown to depend on the isomeric form of the counterion. For hydroxybenzoate, the para-substituted counterion is located within the headgroup region of the surfactant monolayer, and there is of order one counterion for every two surfactant ions. For the ortho-substituted counterion, the degree of counterion binding is higher. There is of order 0.85 counterions for each surfactant ion, and the counterion is located within the hydrophobic region of the monolayer, some 5 A from the center of the headgroup distribution. Similar results were found for the chlorobenzoate counterion, but in that case it was the para-substituted counterion that was more tightly bound and located within the hydrophobic region of the surfactant monolayer. The results for the ortho-substituted hydroxybenzoate and for the para-substituted chlorobenzoate are consistent with those previously reported for the para-tosylate. The results are discussed in the context of the ability of the specific aromatic counterion isomer to promote massive micellar growth, and the results shed light on that mechanism |
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| Beschreibung: | Date Completed 13.06.2006 Date Revised 30.11.2018 published: Print Citation Status MEDLINE |
| ISSN: | 1520-5827 |