Lamellar structures in aqueous solutions of a dimeric surfactant

Citation
A. Knaebel et al., Lamellar structures in aqueous solutions of a dimeric surfactant, LANGMUIR, 16(6), 2000, pp. 2489-2494
Citations number
15
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
LANGMUIR
ISSN journal
07437463 → ACNP
Volume
16
Issue
6
Year of publication
2000
Pages
2489 - 2494
Database
ISI
SICI code
0743-7463(20000321)16:6<2489:LSIASO>2.0.ZU;2-S
Abstract
The effect of salt (KBr) additions on the behavior of the dimeric surfactan t 12-2-12 (ethanediyl-1,2-bis(dodecyldimethylammonium bromide)) has been in vestigated using small-angle neutron scattering and electron microscopy. In the range of surfactant volume fraction 0.08-0.25 only wormlike micelles o r lamellar structures are obtained depending on the temperature and the sal t content. Two different bilayer structures are observed: one, metastable, which obeys the dilution law up to a maximum swelling corresponding to an i ntermicellar distance of similar to 220 Angstrom; the other at equilibrium with a constant swelling corresponding to an interlamellar distance of simi lar to 70 Angstrom. These results confirm the propensity of the gemini surf actants with a short spacer between the polar heads to form collapsed bilay ers structured in stacks.