Properties and Vesicle Formation in Mixed Systems of a Branched Anionic Carboxylate Surfactant and a Cationic Surfactant

Abstract

Abstract Mixtu res of the anionic surfactant AEC7-Na (branched alcohol ether carboxylate) and the cationic surfactant didecylmethylhydroxyethylammonium chloride (DEQ) were systematically investigated. The results showed that the mixtures possess synergisms. The DEQ-AEC7-Na mixture with a mass ratio of 1:1 showed the best result in terms of surface activity, wettability and emulsifying performance. However, when the mass ratio m(DEQ):m(AEC7-Na) = 8:2, the foaming ability and foam stability of the individual surfactants are better. Vesicles smaller than 100 nm coexist with worm-like micelles as soon as a small amount of AEC7- Na is added to DEQ (m(DEQ):m(AEC7-Na) = 8:2). At m(DEQ):m(AEC7-Na) = 4:6 and 2:8, vesicles of approximate ly 80 nm were observed.