Physicochemical investigation of the solubilization of ytterbium nitrate in AOT reverse micelles and liquid crystals

摘要

A wide investigation of the solubilization of the water-soluble salt Yb(NO3)3 in sodium bis(2-ethylhexyl)sulfosuccinate(AOT)reverse micelles and AOT liquid crystals has been carried out.After saturation of water/ AOT/organic solvent w/o rnicroemul-sions with pure Yb(NO3)3,the Yb(NO3)3/AOT composites were prepared by complete evaporation under vacuum of the volatile components(water and organic solvent)of the salt-containing rnicroemulsions.It was observed that these composites can be totally dissolved in pure n-heptane or CCl4,allowing the solubilization of a noticeable amount of Yb(NO3)3 in quite dry apolar media.By UV-vis-NIR,FT-IR,and ~1H NMR spectroscopies,some information on the state of Yb(NO3)3 within AOT reverse micelles were acquired,whereas by small angle X-ray scattering(SAXS),it has been ascertained that Yb(NO3)3 is quite homogeneously distributed as very small clusters among the reverse micelles.An analysis of SAXS and wide-angle X-ray scattering spectra of Yb(NO3)3/AOT composites leads to the hypothesis that,also in these systems,Yb(NO3)3 is dispersed in the surfactant matrix as very small clusters.