title: Interactions of 2,2,2-trifluoroethanol with aqueous micelles of Triton X-100.
abstract: 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.
authors.affiliation: Departamento de Quimica Física II, Facultad de Farmacia, Universidad Complutense, 28040 Madrid, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: García-Blanco
authors.forename: María A
authors.initials: MA
authors.lastname: Elorza
authors.forename: Concepción
authors.initials: C
authors.lastname: Arias
authors.forename: Begoña
authors.initials: B
authors.lastname: Elorza
authors.forename: Ismael
authors.initials: I
authors.lastname: Gómez-Escalonilla
authors.forename: Concepción
authors.initials: C
authors.lastname: Civera
authors.forename: Pedro A
authors.initials: PA
authors.lastname: Galera-Gómez
mesh_terms: 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
chemical_list: D008823:Micelles; D014867:Water; D014270:Trifluoroethanol; D017830:Octoxynol