Aggregate Transitions in Aqueous Solutions of Sodium Dodecylsulfate with a 鈥淕emini-Type鈥?Organic Salt

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• 作者：Defeng Yu ; Maozhang Tian ; Yaxun Fan ; Gang Ji ; Yilin Wang
• 刊名：The Journal of Physical Chemistry B
• 出版年：2012
• 出版时间：June 7, 2012
• 年：2012
• 卷：116
• 期：22
• 页码：6425-6430
• 全文大小：355K
• 年卷期：v.116,no.22(June 7, 2012)
• ISSN：1520-5207

文摘

Effects of a 鈥済emini-type鈥?organic salt 1,2-bis(2-benzylammoniumethoxy) ethane dichloride (BEO) on the aggregation behavior of sodium dodecylsulfate (SDS) have been investigated by turbidity, surface tension, isothermal titration microcalorimetry, dynamic light scattering, cryogenic transmission electron microscopy, ¹H NMR spectroscopy, and differential scanning microcalorimetry. The aggregation behavior of the SDS/BEO mixed aqueous solution shows strong concentration and ratio dependence. For the SDS/BEO solution with a molar ratio of 5:1, large loose irregular aggregates, vesicles, and long thread-like micelles are formed in succession with the increase of the total SDS and BEO concentration. Because BEO has two positive charges, the SDS/BEO solution may consist of the (SDS)₂鈥揃EO gemini-type complex, the SDS鈥揃EO complex and extra SDS. The aggregation ability and surface activity of the SDS/BEO mixture exhibit the characteristics of gemini-type surfactants. Along with the results of DSC and ¹H NMR, the (SDS)₂鈥揃EO gemini-type structure is confirmed to exist in the system. This work provides an approach to construct the surfactant systems with the characteristics of gemini surfactants through intermolecular interaction between a two-charged organic salt and oppositely charged single-chain surfactants.