Effect of Branched Alcohols on Phase Behavior and Rheology of Nonionic Surfactant Systems

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• 作者：Cristina Garc铆a-Iriepa ; Mercedes Valiente
• 刊名：Journal of Chemical & Engineering Data
• 出版年：2014
• 出版时间：August 14, 2014
• 年：2014
• 卷：59
• 期：8
• 页码：2634-2641
• 全文大小：343K
• ISSN：1520-5134

文摘

The effect of single- and double-branched alcohols on the phase and rheological behavior of the laurylsulfobetaine (LSB)/water system was studied, with special attention to the reverse micelles region. In our case, reverse micelle phases behaved as Newtonian fluids where alcohols play the role of solvent. Indeed, it can be concluded that the extension of the reverse micelles phase is determined by the alcohol miscibility in water. Regarding liquid crystals, it is observed that the lamellar phase exhibits gel-like behavior and is the most sensitive to the type of alcohol, affecting the elastic properties and the yield stress values. On the contrary, the hexagonal liquid crystal is barely sensitive to the kind of alcohol. In addition, a comparative study of the phase and rheological behavior of two dodecyl surfactants with different head groups (sulfobetaine LSB, and poly(oxyethylene) Brij-35) as a function of surfactant and tert-butyl alcohol concentrations was performed, revealing two completely different phase diagrams. Whereas the hexagonal liquid crystal appeared only for the LSB/tert-butyl alcohol/water system, the cubic liquid crystal phase appeared for both systems, but the addition of salt was required to stabilize it in the Brij-35 system.