Résumé
The solubilisation of hydrophobic organic molecules in water is relevant in many fields (pharmacy, fragrancy, detergency…). Many studies have been conducted on the use of surfactants, macrocycles or co-solvents to achieve this goal.Cobalta-bis-dicarbollide ([Co(C2B9H11)2]-), otherwise known as COSAN, is an inorganic and ionic nanometric molecule 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 Lalpha/Lβ phases depending on temperature and on its concentration in water). In the current study, we investigated how COSAN affected the solubilization of hydrophobic organic molecules of diverse types and logP values in water, and compared it to sodium dodecylsulfate (SDS), a classical anionic surfactant. In contrast to conventional surfactants, COSAN nano-ion has a higher solubilization efficiency for 2-butanol when COSAN concentration is below its critical aggregation concentration in water. We have used scattering techniques (SANS/SAXS/DLS) to observe the formation of nanometric co-assemblies of COSAN and 2-butanol in water and to decipher, using spectral techniques, an unconventional solubilization mechanism.