Numéro |
J. Phys. II France
Volume 4, Numéro 9, September 1994
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Page(s) | 1585 - 1604 | |
DOI | https://doi.org/10.1051/jp2:1994219 |
J. Phys. II France 4 (1994) 1585-1604
Vesicles as an equilibrium structure of a simple surfactant-water system
L. Cantù1, M. Corti2, E. Del Favero1 and A. Raudino31 Department of Chemistry and Biochemistry, Medical School, University of Milan, via Saldini 50, 20133 Milan, Italy
2 Department of Electronics, University of Pavia, via Abbiategrasso 209, 27100 Pavia, Italy
3 Department of Chemistry, University of Catania, viale A. Doria 6, 95125 Catania, Italy
(Received 1 April 1994, received in final form 20 May 1994, accepted 27 May 1994)
Abstract
Unilamellar vesicles are observed to form spontaneously in dilute water solutions of the ganglioside GM3, which is a double-tailed
biological amphiphile with a saccharidic headgroup. Static and dynamic, both polarized and depolarized, laser light scattering
measurements show that the population of vesicles, of about 500 Å in diameter, is in equilibrium with a very small number
of much larger non spherical objects, which can be schematized as discs with an average radius of 5 000 Å. Hydrophobic chains
in the vesicle bilayer are likely to show a significative degree of interdigitation. Discs are found to disappear completely
when a second amphiphile, GM1, with the same hydrophobic part and a much larger saccharidic headgroup is added. Spontaneous
vesicle formation is associated to the small rigidity of the ganglioside bilayer which may derive from the large mismatch
in the lateral dimension of the polar heads and hydrocarbon chains.
© Les Editions de Physique 1994