Swelling of Lamellar Gel from Catanionic Hydro- and Perfluoro-Carbon Surfactant Mixtures by Refractive-Index Matching |
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Authors: | Yuwen Shen Jingcheng Hao Heinz Hoffmann Yufeng Zhang Wenjing Fan Changai Zhang |
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Institution: | 1. Institute of Agricultural Resources and Environment, Shandong Academy of Agricultural Sciences , Jinan , P. R. China;2. Key Laboratory of Colloid and Interface Chemistry , Shandong University, Ministry of Education , Jinan , P. R. China;3. Universit?t Bayreuth, Bayreuther Zentrum für Kolloide und Grenzfl?chen , Bayreuth , Germany |
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Abstract: | Bilayer swelling behavior of cationic and anionic surfactant mixtures in solution induced by adding glycerin was investigated. The measurements were performed a system, cationic tetradecyltrimetylammonium bromide (TTABr), and anionic sodium perfluorodecanoate (C9F19CO2Na) surfactant mixtures with their stoichiometric mole ratio being exactly 1 in aqueous solution. The non-precipitated phase of cationic and anionic hydro- and perfluoro-carbon surfactant mixtures being the mole ratio of 1:1 could be identified to be lamellar gel phase, which was characterized by freeze-fracture transmission electron microscopy (FF-TEM) and x-ray diffraction (XRD) measurements. Deuterium nuclear magnetic resonance (2H NMR) and rheology were used to characterize the phase transition from the lamellar gel to smaller vesicles. Phase transition from lamellar gel to smaller vesicles can be induced by adding glycerin to replace water. The addition of glycerin lowers the turbidity of the dispersion and swells the interlamellar distance between bilayers, which could be explained by matching of refractive index between solvent and bilayers. |
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Keywords: | Bilayer swelling glycerin refractive index matching |
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