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New Catanionic Mixtures of Didodecyldimethylammonium Bromide/Sodium Dodecylbenzene sulfonate/Water with Special Reference to Spontaneous Formation of Vesicles. II. Size and Shape Analysis by SAXS, Light Scattering, Cryo‐TEM, and Light Microscopy

2005; Taylor & Francis; Volume: 3; Issue: 2-3 Linguagem: Inglês

10.1080/15394450600683477

1539-4468

Suzana Šegota, Đurđica Težak, Yeshayahu Talmon,

Environmental Chemistry and Analysis

Mixed catanionic solutions of sodium dodecybenzenesulfonate (SDBS) and didodecyldimethylammonium bromide (DDAB) have been investigated by dynamic light scattering (DLS) and small‐angle X‐ray scattering (SAXS), with special emphasis on the aggregation behavior and structures of particles spontaneously formed in dependence on the composition of the catanionic mixture SDBS/DDAB/H2O. Phase behavior and particle sizes have been determined. Changes of the mixture composition within two ranges (in the SDBS‐rich corner and in the DDAB‐rich corner in the highly diluted regime) correlated well with the reported changes in the vesicular and micellar sizes. In the diluted SDBS and DDAB regimes mentioned above, monodispersed micelles and monodispersed unilamellar vesicles have been found, respectively. Investigations performed in the solutions using Cryo‐TEM and light microscopy with polarizing equipment confirmed the DLS and SAXS results. The existence of polydispersed unilamellar and oligovesicular vesicles spontaneously formed in the mixtures at w tot=(0.005–0.02) was detected. Micrographs have also shown the giant vesicle formation as well as the coacervate phase formation at w tot=0.0015, x SDBS=0.4. Keywords: AssociateCryo‐TEMDLSCatanionic mixtureMicellesSAXSVesicles Acknowledgments The authors express their gratitude to Dr. Nada Filipović‐Vinceković who enabled them to partly perform the experimental work at the Ruđer Bošković Institute, Zagreb, as well as to Professor Otto Glatter who enabled the SAXS research at the Karl Franzens University in Graz, Austria, and who always kindly helped us with valuable discussion.