engleski

Formation and Microstructures Transformation in Mixtures of Cationic and Anionic Surfactants

In a series of papers it was shown that the formation of various microstructures in mixtures of oppositely charged surfactants aqueous solution depends on the molar ratio and actual concentration of surfactants. General observation includes the coexistence of catanionic vesicles and solid crystalline catanionic salt in a broad concentration range, while catanionic micelles prevail in a high excess of one of the surfactant. Alkyl chain asymmetry is found to play a significant role in the formation and stability of microstructures formed. The relative proportion of crystallites and vesicles and theirs size and shape in coexisting region varied with aging time. The number and size of crystalline particles decreased and size of vesicles increased during aging. The solid crystalline phase was progressively converted to catanionic vesicles indicating curved bilayers as more stable phase. Phase transformations are discussed in terms of surfactant molecular packing constraints and electrostatic interactions in the headgroup region.

catanionic vesicles; catanionic micelles; phase transformation

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