Synthesis and surface properties of anionic gemini surfactants with amide groups
Synthesis and surface properties of anionic gemini surfactants with amide groups
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DOI：
10.1016/j.jcis.2004.03.045
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发表时间：
2004-08-01
影响因子：
9.9
通讯作者：
Esumi, K
中科院分区：
文献类型：
--
作者：
Yoshimura, T;Esumi, K
通过三步反应合成了具有两个碳氢链、两个羧酸基和两个酰胺基团的新型阴离子双子表面活性剂1，2-bis(N-beta-carboxypropanoyl-N-alkylamino)ethane(2C(N)ENAM；n为6、8、10、12或14个碳氢链长)。用平衡表面张力和动态表面张力、稳态荧光光谱和动态光散射技术表征了它们的溶液性质。2C(N)ENAM的表面张力测定表明，其临界胶束浓度(CMC)较低，降低表面张力的效率较高，且在空气/水界面上有很强的吸附作用。Gemini表面活性剂的行为正常，CMC的对数随着链长的增加而线性减小。此外，用PC(20)、CMC/C-20和标准自由能(DeltaG(Mic)(0)和DeltaG(Ads)(0))参数估算了2C(N)EAM的吸附和胶束化行为，它们受碳氢链长的影响很大，并且随着链长的增加，吸附的促进作用大于胶束化作用。动态光散射和荧光猝灭结果表明，在CMC以上的浓度下，2C(N)ENAM形成了较小的胶束，并进一步观察到较大的颗粒。此外，从动态表面张力测量发现，2C(N)ENAM的碳氢链长越短，表面张力下降的速度越快。(C)2004 Elsevier Inc.保留所有权利。
Novel anionic gemini surfactants, 1,2-bis(N-beta-carboxypropanoyl-N-alkylamino)ethane (2C(n)enAm; n is hydrocarbon chain length of 6, 8, 10, 12, or 14), with two hydrocarbon chains, two carboxylate groups, and two amide groups, were synthesized by three-step reactions. Their solution properties were characterized by equilibrium and dynamic surface tension, steady-state fluorescence spectroscopy of pyrene, and dynamic light-scattering techniques. The surface tension measurements of 2C(n)enAm give low critical micelle concentrations (cmc), great efficiency in lowering the surface tension, and strong adsorption at air/water interface. Gemini surfactants behave normally with the logarithm of cmc decrease linearly with the chain length. In addition, adsorption and micellization behavior of 2C(n)enAm was estimated by parameter of pC(20), cmc/C-20, and standard free energy (DeltaG(mic)(0) and DeltaG(ads)(0)); they are significantly influenced by hydrocarbon chain length, and the adsorption is promoted more than the micellization as chain length becomes longer. The results of dynamic light-scattering and fluorescence quenching indicate that small micelles of 2C(n)enAm are observed at the concentrations above the cmc, and further large particles are also seen. Further, from the dynamic surface tension measurements, it is found that the shorter hydrocarbon chain length of 2C(n)enAm, the faster the rate of decrease of surface tension. (C) 2004 Elsevier Inc. All rights reserved.