Origin of the Sphere-to-Rod Transition in Cationic Micelles with Aromatic Counterions: Specific Ion Hydration in the Interfacial Region Matters
| Autor: | Dino Zanette, Laurence S. Romsted, Iolanda M. Cuccovia, Yan Geng, Linda J. Magid, Hernan Chaimovich, Sandro Froehner |
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| Rok vydání: | 2004 |
| Předmět: |
chemistry.chemical_classification
Morphology (linguistics) Inorganic chemistry Substituent Cationic polymerization Salt (chemistry) Surfaces and Interfaces Trapping Condensed Matter Physics Photochemistry Mole fraction Micelle chemistry.chemical_compound chemistry Electrochemistry General Materials Science Counterion Spectroscopy |
| Zdroj: | Langmuir. 21:562-568 |
| ISSN: | 1520-5827 0743-7463 |
| Popis: | Sphere-to-rod transitions of cetyltrimethylammonium (CTA+) micelles with dichlorobenzoate counterions are remarkably substituent dependent. Simultaneous estimates of the interfacial molarities of H2O, MeOH, and Cl- and 2,6- and 3,5-dichlorobenzoate (2,6OBz and 3,5OBz) counterions were obtained by the chemical trapping method in mixed micelles of CTACl/CTA3,5OBz and CTACl/CTA2,6OBz without added salt. Increasing the CTA3,5OBz mole fraction produces a marked concurrent increase in interfacial 3,5OBz- and a decrease in interfacial H2O concentrations through the sphere-to-rod transition. No abrupt concentration changes are observed with increasing CTA2,6OBz mole fraction. Counterion-specific changes in the interfacial water concentration may be a major contributor to the delicate balance of forces governing micellar morphology. |
| Databáze: | OpenAIRE |
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