Interactions of 2,2,2-trifluoroethanol with aqueous micelles of Triton X-100.
The effect of 2,2,2-trifluoroethanol (TFE) on micellar properties of Triton X-100 (TX-100) in aqueous solutions was investigated by cloud point (CP), viscosity, surface tension, and fluorescence techniques. The critical micelle concentration (CMC) values of the corresponding mixtures were obtained by the pyrene 1:3 ratio method and by surface tension data using the pendant drop technique. All the techniques provided about the same values for the CMC. Up to 0.83 M TFE increased the CMC by 30%. The small increase in the CMC is consistent with a slight increase in the solubility of the TX-100. Fluorescence measurements indicate that the TFE decreased the aggregation number by about 30%. The CP decrease and the intrinsic viscosity increase with TFE concentration are consistent with a preferential interaction of TFE with TX-100 micelles. TFE molecules form hydrophobic domains in the micellar layer palisade because they hydrogen bond with the oxyethylene group in TX-100. The intrinsic viscosity data are consistent with an increase in micelle hydrodynamic radius owing to the presence of TFE.
García-Blanco
Francisco
F
Departamento de Quimica Física II, Facultad de Farmacia, Universidad Complutense, 28040 Madrid, Spain.
Elorza
María A
MA
Arias
Concepción
C
Elorza
Begoña
B
Gómez-Escalonilla
Ismael
I
Civera
Concepción
C
Galera-Gómez
Pedro A
PA
D002623:Chemistry Techniques, Analytical / Q000379:methods; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D008823:Micelles; D017830:Octoxynol / Q000737:chemistry*; D014270:Trifluoroethanol / Q000737:chemistry*; D014867:Water
D008823:Micelles; D014867:Water; D014270:Trifluoroethanol; D017830:Octoxynol