Catanionic micelles as a model to mimic
biological membranes in the presence of anesthetic alcohols.
Mahiuddin Sekh; Zech Oliver; Raith Sabine; Touraud Didier; Kunz Werner
Langmuir : the ACS journal of surfaces and colloids
25(21) (2009) 12516-21.
Abstract
We show here the influence of n-alcohols (C(2)OH-C(8)OH) on the solubility
behavior of cationic-anionic surfactant mixtures, so-called
"catanionics". We studied catanionics of different compositions
composed of sodium dodecyl sulfate (SDS)/cetyltrimethylammonium bromide (CTAB)
and sodium dodecanoate (SDod)/CTAB mixtures. Interestingly, with a molar excess
of SDS, long chain n-alcohols (C(4)OH-C(8)OH) significantly depress the
solubility temperature of the SDS+CTAB catanionic and increase the kinetic
stability of the solution. The visual observations of solubility temperatures
of catanionics were further confirmed by differential scanning calorimetry
(DSC) measurements. For the catanionics a multistep solubilization was observed
by DSC, for which the sulfate headgroup is responsible. This was probed by
replacing SDS by SDod. A remarkable analogy was found between the influence of
the alcohols on the solubility patterns of the catanionic mixtures and on the
anesthesia of tadpoles. Possible reasons for this analogy are discussed also in
this paper. |
