On the structure of isotropic phases in lipid-water systems

✍ Scribed by Kåre Larsson

• Publisher: Elsevier Science
• Year: 1972
• Tongue: English
• Weight: 726 KB
• Volume: 9
• Category: Article
• ISSN: 0009-3084
• DOI: 10.1016/0009-3084(72)90001-1

✦ Synopsis

The structure of iso~ropic phases occurring in aqueous lipids systems are discussed on the basis of some new experimental results. Characteristic effects in the Raman spectra due to the hydrocarbon chain conformation are shown. It is proposed that the amphiphilic solution (phase L2) has a structure closely related to that of the mesophase obtained on cooling, the transition point to the liquid phase representing a loss in long-range order only. Differences in water swelling properties of this liquid phase corresponding to differences in structure according to such a phase transition mechanism are demonstrated experimentally. A simple model for the transition between spherical and cylindrical micelles in the water solution (phase LI), based on minimization of the surface-to-volume ratio, is compared with the observed transitions. The behaviour of micro-emulsions in relation to the two liquid phases LI and L2 is discussed. Finally evidences is given for the existence of a general cubic structure type with closed water aggregates in a lipid matrix, and a model based on space-filling polyhedra is proposed.