MORPHOLOGY OF AQUEOUS SODIUM DIBUTYL PHOSPHATE ESTIMATED FROM MOLECULAR TO SUPERSTRUCTURAL LEVELS

The morphological and structural characteristics of aqueous sodium dib utyl phosphate (DBP) have been investigated at all levels from molecul ar to superstructural by using polarized microscopy, light scattering, small-angle X-ray scattering, and nuclear magnetic resonance techniqu es. Above a certain concentration, the aqueous solutions separated int o two liquid phases, one of which was spontaneously birefringent. The birefringent phase first separated in the form of spherulites, in whic h the hydrocarbon chains are oriented parallel to the radial direction . With increasing concentration, a transition from spherulitic to rodl ike texture occurred and the system finally became a continuous birefr ingent phase. The spherulitic and/or rodlike textures were gradually d estroyed with increasing temperature and disappeared at 55 degrees C. However, the X-ray scattered intensity distribution indicated that des pite the disruption of superstructures at 70 degrees C, the bilayer bl ocks (assemblies) are maintained without separating into bilayer micel l units which can be regarded as two weakly interacting monolayer comp osed of DBP. Above a critical concentration, the longitudinal and tran sverse relaxation times predicted that the motion of carbons is strong ly restricted by hydrocarbon chain interaction.