Résumé
It is known that surfactant micelles solubilize hydrophobic organic molecules by their aggregation mechanism, controlled by the hydrophobic effect. In the current study, we investigated how nanometric anion affected the solubilization of hydrophobic organic molecules of diverse types and logP values in water. Metalla-bis-dicarbollides, such as COSAN [Co(C2B9H11)2]-, are inorganic and ionic nanometric structures characterized by a very low charge density. Although missing a traditional amphiphilic structure, COSAN stands out for its surfactant-like characteristics, such as surface activity and self-assembly ability (vesicles, micellar and L phases depending on its concentration in water). In contrast to conventional surfactants, COSAN nanoion has a higher solubilization efficiency when it is in a monomeric state and at concentration below its critical aggregation concentration. We have used scattering techniques and thus contrast variation (SANS using a specific deuteration of 2-butanol in a JCNS proposal /SAXS /DLS) to observe the formation of nanometric co-assemblies in water and to decipher, using spectral techniques, an unconventionnal solubilization mechanism. Comparison with SDS surfactant will be shown in term of solubilization efficiencies and for various hydrophobic compounds listed above. This work aims at the better understanding of COSAN-hydrophobic organic compounds interactions that are essential for the biological and medical applications of COSAN.