Solutions of alkali soaps and water in fatty acids X. The basic structure of the molecules and the size of the particles of acid octanoates in the L₂-phase at water contents below 40%

Abstract

The acid sodium octanoate molecules in the isotropic liquidL ₂-phase of the system sodium octanoate-octanoic acid-water have the same basic structure in the whole region, from non-aqueous melt up to a water content of 40 %. This molecular structure is characterized by amphiphilic units oriented with the polar groups directed inwards and bound to each other, forming a central core from which the hydrocarbon chains protrude in at least two opposite directions. The size of the molecules increases due to the incorporation of water, and their shape changes from spherical to elongated rods or ribbons. They occur as monomers or dimers; no aggregation to lasting large particles has been observed. However, transient agglomerates of the free molecules seem to occur.