不同辐照条件下非离子光响应表面活性剂的自组装：小角中子散射和低温透射电子显微镜研究

Self-assembly of a nonionic photoresponsive surfactant under varying irradiation conditions: a small-angle neutron scattering and cryo-TEM study.

作者信息

Shang Tiangang, Smith Kenneth A, Hatton T Alan

机构信息

Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139-4307, USA.

出版信息

Langmuir. 2006 Feb 14;22(4):1436-42. doi: 10.1021/la052215y.

DOI:10.1021/la052215y

PMID:16460058

Abstract

We have used small-angle neutron scattering (SANS), and cryogenic transmission electron microscopy (cryo-TEM) to determine the structure of aggregates formed by the photoresponsive surfactants diethylene glycol mono(4',4-butyloxy, butyl-azobenzene) (C4AzoOC4E2) and diethylene glycol mono(4',4-hexyloxy, butyl-azobenzene) (C4AzoOC6E2) under different illumination conditions. At high concentrations, the self-assembly behavior of these surfactants changes remarkably in response to different radiation conditions. The trans isomers assemble into bilamellar (C4AzoOC4E2) and unilamellar (C4AzoOC6E2) vesicles, while the cis isomers (under UV light) form bicontinuous phases. These light-induced structural changes are attributed to a change in the sign of the Gaussian rigidity, which is the direct result of azobenzene photoisomerization.

摘要

我们使用小角中子散射（SANS）和低温透射电子显微镜（cryo-TEM）来确定光响应性表面活性剂二甘醇单（4'，4-丁氧基，丁基偶氮苯）（C4AzoOC4E2）和二甘醇单（4'，4-己氧基，丁基偶氮苯）（C4AzoOC6E2）在不同光照条件下形成的聚集体结构。在高浓度下，这些表面活性剂的自组装行为会因不同的辐射条件而发生显著变化。反式异构体组装成双层（C4AzoOC4E2）和单层（C4AzoOC6E2）囊泡，而顺式异构体（在紫外光下）形成双连续相。这些光诱导的结构变化归因于高斯刚性符号的变化，这是偶氮苯光异构化的直接结果。