Analytical Sciences

Abstract − Analytical Sciences, 20(11), 1501 (2004).

Dynamic Behaviors of Molecular Assemblies at Liquid/Liquid Interfaces Studied by Time-Resolved Quasi-Elastic Laser Scattering Spectroscopy
Hiroharu YUI,*,** Yasuhiro IKEZOE,** and Tsuguo SAWADA*,**
*CREST, Japan Science and Technology Agency (JST), Nanoarchitectonics Research Center (NARC), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 4, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562, Japan
**Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5-603 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan
The dynamic behaviors of molecular assemblies at two immiscible liquid interfaces are intriguing topics in many fields of science and technology. However, it is generally difficult to investigate the dynamic behaviors of such molecular assemblies because of the buried nature of liquid/liquid interfaces. In the present paper, our recent investigations on dynamic behaviors of various molecular self-assemblies at liquid/liquid interfaces are reviewed. We monitored dynamic behaviors of the molecular assemblies by time-resolved quasi-elastic laser scattering (TR-QELS) and fluorescent spectroscopy. The former method allows us to monitor the change in interfacial tension with millisecond time-resolution. As molecular assemblies, bis(2-ethylhexyl)sulfosuccinate (AOT) microemulsion, phospholipid biomembrane models, and liposome-DNA complexes have all been studied, since they are relevant in material sciences and biological technologies. At liquid/liquid interfaces, these molecular assemblies showed characteristic behaviors. We review the finding of rebound response of the interfacial tension at the liquid/liquid interface induced by the adsorption of the AOT microemulsion. We monitored the hydrolysis reaction of phospholipid biomembrane models formed at oil/water interfaces, observing the different types of behavior of liposome-DNA complexes at biomembrane models with different kinds of phospholipids.