Aggregation properties and mixing behavior of hydrocarbon, fluorocarbon, and hybrid hydrocarbon-fluorocarbon cationic dimeric surfactants
Aggregation properties and mixing behavior of hydrocarbon, fluorocarbon, and hybrid hydrocarbon-fluorocarbon cationic dimeric surfactants
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DOI：
10.1021/la0008075
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发表时间：
2000-12-12
期刊：
影响因子：
3.9
通讯作者：
Talmon, Y
中科院分区：
文献类型：
--
作者：
Oda, R;Huc, I;Talmon, Y
介绍了具有一个或两个全氟烷基链的阳离子二聚（双子）表面活性剂的合成、相行为和混合性能，并与类似烃类表面活性剂进行了比较。两亲物的二聚特性与氟碳链的高疏水性的组合导致非常低的临界胶束浓度值和本体溶液中的表面活性剂与聚集体中的表面活性剂之间的交换的异常低的特征时间。这导致在NMR时间尺度上的缓慢交换，这允许通过NMR对胶束化和共胶束化进行实际研究。相对于聚集体的形态，氟碳两亲物不简单地表现为更疏水的两亲物。相反，它们组装成各种结构，包括非常稳定的单层和多层囊泡，在其烃类似物中看不到。混合烃-氟碳化合物二聚表面活性剂表现出两个家族的特征。特别地，它与烃或氟碳表面活性剂混合，而后两者经历宏观相分离。
The synthesis, phase behavior, and mixing properties of cationic dimeric (gemini) surfactants having one or two perfluoroalkyl chains is described and compared to that of analogue hydrocarbon surfactants. The combination of the dimeric character of the amphiphiles with the high hydrophobicity of the fluorocarbon chains leads to very low critical micelle concentration values and unusually low characteristic times of exchange between surfactants in the bulk solution and surfactants in the aggregate. This results in slow exchange on the NMR time scale, which allows a practical study of micellization and comicellization by NMR. With respect to the morphology of the aggregates, the fluorocarbon amphiphiles do not simply behave as more hydrophobic amphiphiles. Instead, they assemble into various structures including very stable unilamellar and multilamellar vesicles not seen in their hydrocarbon analogues. The hybrid hydrocarbon-fluorocarbon dimeric surfactant exhibits features of both families. In particular it mixes with either hydrocarbon or fluorocarbon surfactants, whereas the latter two undergo a macroscopic phase separation.