Thèse de doctorat en Chimie macromoléculaire et supramoléculaire
Sous la direction de Véronique Pimienta.
Soutenue en 2006
à Toulouse 3 .
Pas de résumé disponible.
Periodic Marangoni instabilities in biphasic liquid/liquid system : role and properties of tensioactive ion pairs
Oscillations of the electrical potential and interfacial tension have been studied during mass transfer in water/dichloromethane biphasic systems: CTAB/picric acid and SDS/TAAB for which, the chain length of the tetraalkylammonium was varied (from ethyl to butyl). A detailed analysis of the signals recorded allowed us to confirm the hydrodynamic origin (Marangoni instability) of the oscillations. We have determined the physico-chemical properties of all species involved (partition and adsorption constant, molecular area, and association constant of the ion pairs). For this, measurements of the surface tension, UV/Visible spectrophotometry and mass spectrometry have been performed. For the SDS/TAAB system, we have observed increasing association of TAADS ion pairs with chain length. We have also carried out theoretical calculations (DFT, Ab-initio) to highlight a geometry supporting the hydrophobic interactions between the two ions.