Fluorescence Study of Premicellar Aggregation in Cationic Gemini Surfactants
| Autor: | Joann H. Mathias, Milton J. Rosen and, Lesley Davenport |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
chemistry.chemical_classification
Aggregation number Inorganic chemistry Surfaces and Interfaces Condensed Matter Physics Micelle Fluorescence spectroscopy chemistry.chemical_compound chemistry Pulmonary surfactant Phenylene Critical micelle concentration Electrochemistry Pyrene Physical chemistry General Materials Science Spectroscopy Alkyl |
| Zdroj: | Langmuir. 17:6148-6154 |
| ISSN: | 1520-5827 0743-7463 |
| DOI: | 10.1021/la010852s |
| Popis: | The aggregation behavior of four series of bis(quaternary ammonium halide) surfactants (gemini surfactants) having diethyl ether, dihydroxybutyl, monohydroxypropyl, and dimethylene phenylene spacer groups has been studied using steady-state and time-resolved fluorescence spectroscopy. Aggregation numbers were determined using the time-resolved single photon counting method with pyrene as the probe. At certain surfactant concentrations, aggregation numbers of 2, expressed as gemini molecules per micelle, were obtained in all four series when the number of carbon atoms in the alkyl chain length (n) increased beyond a maximum. These long-chain geminis also have a critical micelle concentration (cmc) greater than expected on the basis of plots of log cmc vs n for the shorter chain homologues. This deviation has been attributed to the formation of premicellar aggregates in the surfactant concentration region between the observed and the expected cmc values. The aggregation numbers obtained here indeed point to... |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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