Zhu Xiaoyu, Du Na, Song Ruiying, Hou Wanguo, Song Shue, Zhang Renjie
Key Laboratory of Colloid and Interface Chemistry (Ministry of Education), Shandong University , Jinan 250199, People's Republic of China.
Langmuir. 2014 Oct 7;30(39):11543-51. doi: 10.1021/la502965q. Epub 2014 Sep 26.
We report novel vesicles composed of the zwitterionic surfactant lauryl sulfobetaine (LSB), which is a simple single-tailed surfactant (STS). The novel vesicles spontaneously formed from LSB micellar solutions with the mediation of a rough glass surface (RGS) in the absence of any cosurfactants or additives. Importantly, the obtained STS vesicles displayed good stability upon long-term storage, exposure to high temperature, and freeze-thawing after the RGS was removed. The pH of the LSB solution (4.0-9.0) and the presence of NaCl (1.0 × 10(-5) and 1.0 × 10(-4) mol/L) in the LSB solution had no obvious influence on the formation and stability of the vesicles. The adsorption configuration of LSB on the RGS was investigated via water contact angle measurements and atomic force microscope observations. The results showed that LSB adsorption bilayers could form on the RGS, and the bilayer adsorption of LSB on the RGS and the roughness of the solid surface played a key role in the vesicle formation. A possible mechanism for the RGS-mediated formation of LSB vesicles is proposed: LSB micelles and molecules adsorb on the RGS to form curved bilayers, and the curved bilayers are then detached from the RGS and close to form vesicles. To the best of our knowledge, this is the first report of LSB alone forming vesicles. This finding extends our understanding of the nature of vesicle systems.
我们报道了由两性离子表面活性剂月桂基磺基甜菜碱（LSB）组成的新型囊泡，它是一种简单的单尾表面活性剂（STS）。在没有任何助表面活性剂或添加剂的情况下，新型囊泡由LSB胶束溶液在粗糙玻璃表面（RGS）的介导下自发形成。重要的是，在去除RGS后，所得的STS囊泡在长期储存、高温暴露和冻融处理后仍表现出良好的稳定性。LSB溶液的pH值（4.0 - 9.0）以及LSB溶液中NaCl的存在（1.0×10⁻⁵和1.0×10⁻⁴ mol/L）对囊泡的形成和稳定性没有明显影响。通过水接触角测量和原子力显微镜观察研究了LSB在RGS上的吸附构型。结果表明，LSB吸附双层可以在RGS上形成，并且LSB在RGS上的双层吸附以及固体表面的粗糙度在囊泡形成中起关键作用。提出了一种RGS介导的LSB囊泡形成的可能机制：LSB胶束和分子吸附在RGS上形成弯曲双层，然后弯曲双层从RGS上脱离并闭合形成囊泡。据我们所知，这是关于LSB单独形成囊泡的首次报道。这一发现扩展了我们对囊泡系统性质的理解。
