Demicellization of a mixture of cationic-anionic hydrogenated/fluorinated surfactants through selective inclusion by alpha- and beta-cyclodextrin
The interactions between alpha- and beta-cyclodextrin (alpha-/beta-CD) and an equimolar mixture of octyltriethylammonium bromide (OTEAB) and sodium perfluorooctanoate (SPFO) were studied by 1H and 19F NMR, surface tension, conductivity, and dynamic light scattering. It was shown that beta-CD could d...
| Publié dans: | Langmuir : the ACS journal of surfaces and colloids. - 1985. - 24(2008), 19 vom: 07. Okt., Seite 10654-64 |
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| Auteur principal: | |
| Autres auteurs: | , , |
| Format: | Article en ligne |
| Langue: | English |
| Publié: |
2008
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| Accès à la collection: | Langmuir : the ACS journal of surfaces and colloids |
| Sujets: | Journal Article |
| Résumé: | The interactions between alpha- and beta-cyclodextrin (alpha-/beta-CD) and an equimolar mixture of octyltriethylammonium bromide (OTEAB) and sodium perfluorooctanoate (SPFO) were studied by 1H and 19F NMR, surface tension, conductivity, and dynamic light scattering. It was shown that beta-CD could destroy the mixed micelles of OTEAB-SPFO by selective inclusion of SPFO. As beta-CD was added, the system was observed to undergo a process like this: beta-CD preferentially included SPFO to form 1:1 beta-CD/SPFO complexes. As the inclusion of SPFO was almost saturated, the mixed micelles broke and all OTEAB was released and exposed to aqueous surroundings. Then 1:1 beta-CD/OTEAB and 2:1 beta-CD/SPFO complexes significantly formed simultaneously. Contrary to beta-CD, alpha-CD exhibited selective inclusion to OTEAB and only weak association with SPFO. alpha-CD could also destroy the mixed micelles of OTEAB-SPFO; however, the demicellization ability of alpha-CD is much smaller than that of beta-CD. These conclusions were also well supported by the calculations of binding constants and DeltaG degrees . Different from the complexes of CD/conventional surfactants, the complexes of beta-CD/SPFO or alpha-CD/OTEAB formed by selective inclusion of CD in the mixed cationic-anionic surfactants may have contributed to the surface activity of the aqueous mixtures. The complexes of alpha-CD/OTEAB showed much more significant contribution to the surface activity than that of the complexes of beta-CD/SPFO |
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| Description: | Date Completed 28.10.2008 Date Revised 01.10.2008 published: Print-Electronic Citation Status PubMed-not-MEDLINE |
| ISSN: | 1520-5827 |
| DOI: | 10.1021/la8014095 |