Hypothesis

Ultra-long tailed zwitterionic surfactants often form aqueous wormlike elastic micelles, whereas the shorter ones mainly exhibit spherical viscous micelles. Anionic surfactants are widely used to tune the micellar morphology from spherical into wormlike. Systematic investigations in the molecular level are insightful to understand the viscoelasticity regulative mechanism.

Experiments

Anionic/zwitterionic hybrid wormlike micelles are composed of sodium alkylsulfate (SAS) homologues and dodecyl dimethyl amidopropyl hydroxyl sulfobetaine (DHSB). The formation of wormlike micelles was studied by employing rheometer, cryogenic transmission electron microscopy (cryo-TEM) and small angle X-ray scattering (SAXS) techniques. The effects of surfactant concentration, molar ratio, anionic surfactant chain length and temperature were investigated systematically.

Findings

SAS promoted the formation of SAS/DHSB hybrid wormlike micelles. The increase in both chain length and molar ratio (x_SAS) of SAS are advantageous in the enhancement of viscosity. Interestingly, sodium hexadecylsulfate (SHS) endowed elastic wormlike micelles with thermally insensitive viscosity below its Krafft temperature (T_k), which was distinguished from the viscous ones formed by sodium octylsulfate (SOS). SAXS results showed that the size of SAS/DHSB wormlike micelles was primarily determinate by surfactants with longer hydrophobic tails.

中文翻译：

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阴离子/两性离子蠕虫状胶束从粘性域逐渐转变为弹性域：揭示阴离子表面活性剂链长的影响

假设

超长尾两性离子表面活性剂通常形成水性蠕虫状弹性胶束，而较短的两性离子表面活性剂主要表现出球形粘性胶束。阴离子表面活性剂广泛用于将胶束形态从球形调整为蠕虫状。分子水平的系统研究对于理解粘弹性调节机制具有深刻的见解。

实验

阴离子/两性离子杂化蠕虫状胶束由烷基硫酸钠 (SAS) 同系物和十二烷基二甲基氨基丙基羟基磺基甜菜碱 (DHSB) 组成。通过使用流变仪、低温透射电子显微镜 (cryo-TEM) 和小角 X 射线散射 (SAXS) 技术研究了蠕虫状胶束的形成。系统地研究了表面活性剂浓度、摩尔比、阴离子表面活性剂链长和温度的影响。

发现

SAS 促进了 SAS/DHSB 混合蠕虫状胶束的形成。SAS的链长和摩尔比（ x _SAS ）的增加有利于粘度的提高。有趣的是，十六烷基硫酸钠 (SHS) 赋予弹性蠕虫状胶束以低于其克拉夫特温度 ( T _k ) 的热不敏感粘度，这与辛基硫酸钠 (SOS) 形成的粘性胶束不同。SAXS 结果表明，SAS/DHSB 蠕虫状胶束的大小主要由具有较长疏水尾的表面活性剂决定。