Department of Chemistry, Indian Institute of Technology, Kharagpur-721 302, India.
Langmuir. 2011 May 3;27(9):5184-92. doi: 10.1021/la1040147. Epub 2011 Apr 4.
The physicochemical properties, such as critical micelle concentration (cmc), surface tension at cmc (γ(cmc)), and surface activity parameters of the mixtures of a new amino acid-based zwitterionic surfactant, N-(n-dodecyl-2-aminoethanoyl)-glycine (C(12)Gly) and an anionic surfactant, sodium dodecyl sulfate (SDS) at different molar fractions, X(1) (= [C(12)Gly]/([C(12)Gly] + [SDS])) of C(12)Gly were studied. A synergistic interaction was observed between the surfactants in mixtures of different X(1). The self-organization of the mixtures at different molar fractions, concentrations, and pH was investigated. Fluorescence depolarization studies in combination with dynamic light scattering, and transmission electron microscopic and confocal fluorescence microscopic images suggested the formation of bilayer vesicles in dilute solutions of SDS rich mixtures with X(1) ≤ 0.17 in the pH range 7.0 to 9.0. However, the electronic micrographs showed structures with fingerprint-like texture in moderately dilute to concentrated C(12)Gly/SDS mixture at X(1) = 0.50. The vesicles were observed to transform into small micelles upon lowering the solution pH and upon increase of total surfactant concentration in mixtures with X(1) ≤ 0.17. However, decrease of SDS content transformed vesicles into wormlike micelles. The structural transitions were correlated with bulk viscosity of the binary mixtures.
该物理化学性质，如临界胶束浓度（cmc），表面张力在 cmc（γ（cmc））和表面活性参数的混合物的一种新型氨基酸型两性离子表面活性剂，N-（正十二烷基-2-氨基乙酰基）-甘氨酸（C（12）Gly）和阴离子表面活性剂，十二烷基硫酸钠（SDS）在不同的摩尔分数，X（1）（=[C（12）Gly] /（[C（12）Gly]+[SDS]））的 C（12）Gly 进行了研究。在不同 X（1）的混合物中观察到表面活性剂之间存在协同相互作用。在不同摩尔分数、浓度和 pH 值下研究了混合物的自组织。荧光偏振研究与动态光散射、透射电子显微镜和共焦荧光显微镜图像相结合表明，在 pH 值为 7.0 至 9.0 的范围内，SDS 丰富混合物的稀溶液中形成双层囊泡，X（1）≤0.17。然而，电子显微镜照片显示在中等稀至浓 C（12）Gly/SDS 混合物中 X（1）=0.50 时有指纹状纹理的结构。当溶液 pH 值降低且 X（1）≤0.17 的混合物中总表面活性剂浓度增加时，观察到囊泡转变为小胶束。然而，降低 SDS 含量将囊泡转变为蠕虫状胶束。结构转变与二元混合物的体粘度相关。
