title: On the interpretation of transport properties of sodium cholate and sodium deoxycholate in binary and ternary aqueous mixtures.
abstract: Sodium cholate (NaC) and sodium deoxycholate (NaDC) in binary and ternary aqueous mixtures were investigated by means of surface tension, electron paramagnetic resonance spectroscopy (EPR), small angle neutron scattering (SANS) and mutual diffusion coefficient analysis. Concerning the NaC-H(2)O and NaDC-H(2)O binary mixtures, the surface tension, EPR and diffusion measurements confirmed the formation of micelles above a well detectable critical concentration. The SANS data indicated for both systems, the formation of ellipsoidal micelles whose major axis increased with concentration and minor axis remained constant. The data were interpreted under the assumption that aggregate growth occurred via hydrogen bonding of small aggregates along one preferential direction. For the NaC-NaDC-H(2)O ternary mixtures, the surface tension and EPR results were in good agreement with the Clint model prediction for the ideal mixed micellization. Based on this model, the SANS data enabled a complete description of the mixed aggregates in terms of dimensions, composition and concentration. In turn, this strategy allowed for a satisfactory interpretation of the main and cross-term diffusion coefficient trends, which are quite complex.
authors.affiliation: CSGI-Consorzio interuniversitario per lo sviluppo dei Sistemi a Grande Interfase and Università degli Studi di Napoli Federico II, Dipartimento di Chimica, via Cinthia, 80126 Napoli, Italy.
authors.forename: Gaetano
authors.initials: G
authors.lastname: Mangiapia
authors.forename: Gerardino
authors.initials: G
authors.lastname: D'Errico
authors.forename: Fabio
authors.initials: F
authors.lastname: Capuano
authors.forename: Ornella
authors.initials: O
authors.lastname: Ortona
authors.forename: Richard K
authors.initials: RK
authors.lastname: Heenan
authors.forename: Luigi
authors.initials: L
authors.lastname: Paduano
authors.forename: Roberto
authors.initials: R
authors.lastname: Sartorio
mesh_terms: D003840:Deoxycholic Acid / Q000737:chemistry*; D004058:Diffusion; D004578:Electron Spin Resonance Spectroscopy; D033363:Neutron Diffraction; D053838:Scattering, Small Angle; D020358:Sodium Cholate / Q000737:chemistry*; D013500:Surface Tension; D014867:Water / Q000737:chemistry*
chemical_list: D003840:Deoxycholic Acid; D014867:Water; D020358:Sodium Cholate