Surfactant phase science

Variations in both the lipophilic and the hydrophilic structural elements of synthetic surfactant molecules and phase studies of the compounds continue apace. Lyotropic nematic liquid crystals may exist in selected non-ionics (C16E6), and ‘intermediate’ liquid crystal phases continue to be found. As with ionic surfactants, attaching two lipophilic chains to a polyether non-ionic group has been shown to promote formation of the lamellar liquid crystal phase (if the chains are sufficiently long). Considerable attention is being given to catanionic surfactants (ionic surfactants in which both ions are amphophilic), but as these compounds are often formed in situ, interpretation of the present data is often uncertain. Ternary systems of singly and doubly charged cationic surfactants and water have been studied, as have quaternary systems consisting of a semipolar amine oxide, an anionic (or a cationic) surfactant, oil and water. The profound influence that amphiphilic oils have on aqueous surfactant behavior (found earlier in ionic surfactant-oil-water systems) has now been documented in a non-ionic system. The phase behavior of perfume oils in combination with several surfactants has been studied.