Zwitterionic heterogemini surfactants containing ammonium and carboxylate headgroups. 1. Adsorption and micellization
Zwitterionic heterogemini surfactants with two hydrocarbon chains and two different hydrophilic groups, N,N-dimethyl-N-[2-(N'-alkyl-N'-beta-carboxypropanoylamino)ethyl]-1-alkylammonium bromides (2C(n)AmCa, where n represents the hydrocarbon chain lengths of 8, 10, 12, and 14), were synthes...
| Veröffentlicht in: | Langmuir : the ACS journal of surfaces and colloids. - 1992. - 21(2005), 7 vom: 29. März, Seite 2682-8 |
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| Format: | Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2005
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| Zugriff auf das übergeordnete Werk: | Langmuir : the ACS journal of surfaces and colloids |
| Schlagworte: | Journal Article |
| Zusammenfassung: | Zwitterionic heterogemini surfactants with two hydrocarbon chains and two different hydrophilic groups, N,N-dimethyl-N-[2-(N'-alkyl-N'-beta-carboxypropanoylamino)ethyl]-1-alkylammonium bromides (2C(n)AmCa, where n represents the hydrocarbon chain lengths of 8, 10, 12, and 14), were synthesized by N,N-dimethylethylenediamine with alkyl bromide, followed by reaction with succinic anhydride. One of the hydrophilic groups is a carboxylate anion, and the other is an ammonium cation. Their physicochemical properties were characterized by measuring equilibrium and dynamic surface tension, fluorescence intensity of pyrene, and light-scattering intensity. A relationship between a logarithm of critical micelle concentration (cmc) and hydrocarbon chain length showed a linear decrease upon increasing chain length and then a departure from linearity at n = 14. This is due to the existence of premicellar aggregations at concentrations below the cmc for n = 14. The surface tension of 2C(n)AmCa reached 27-30 mN m(-1) at each cmc, indicating efficiencies typical of hydrocarbon chain surfactants. The adsorbing rate at the air/water interface became slow with an increase of the chain length. From the fluorescence intensity ratios of 373 and 384 nm using pyrene as a probe, for n = 8, 10, and 14, the pyrene was solubilized in surfactant micelles at around the cmc, whereas for n = 12 the pyrene was solubilized from a concentration of 10-fold the cmc. The scattering intensities by dynamic light scattering also increased from around these concentrations for each chain length, showing the formation of aggregates in solution |
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| Beschreibung: | Date Completed 14.06.2006 Date Revised 22.03.2005 published: Print Citation Status PubMed-not-MEDLINE |
| ISSN: | 1520-5827 |