Fluctuations and Structure at Liquid-Liquid Interfaces

这是一个新的项目，将使用同步加速器x射线表面散射来研究多组分流体中液-液界面处的波动和结构。这些实验将探索分子有序性和热涨落在决定界面现象中的作用。感兴趣的领域如下。(1)研究了体相内有序度不同时，油-微乳液和微乳液-水界面的界面分布。(2)研究薄膜中短距离脉动界面相互作用的行为。(3)在较宽的链长范围内和在主体烷烃熔融温度附近的温度下，研究了二元烷-水界面的行为。(4)当界面起伏的幅度在一到两个数量级变化时，研究了在定义良好的化学体系中液-液界面上的表面活性剂的组织。通过将一根销子插入水面，表面张力的存在是显而易见的。这种张力是由从液体主体中提取分子并产生单位面积的表面或界面所需的自由能决定的。这种能量取决于界面上的分子结构。许多依赖于界面结构的过程发生在液-液界面，例如分子在界面上的传输。这些过程对于制造新材料、了解界面化学以及在生物界面(如膜)中都很重要。不幸的是，关于这种界面结构的实验信息很少。我们建议使用强大的同步加速器X射线源来研究液-液界面上的这种结构。这些研究将包括对日常生活(和工业制造)中常见的油水界面的测量，也包括对一些本身剧烈波动的外来界面的测量。*p：\图卢兹\absi98

w:\awards\awards96\num.doc 9700975 Schlossman Technical: This is a new project in which synchrotron x-ray surface scattering will be used to investigate fluctuations and structure at the liquid-liquid interface in multi-component fluids. These experiments will probe the role of molecular ordering and thermal fluctuations in determining interfacial phenomena . The areas of interest are as follows. (1) Study of interfacial profiles at the oil-microemulsion and microemulsion-water interfaces as the degree of internal order in the bulk phases is varied. (2) Study of the behavior of fluctuating interfaces interacting over short distances in thin wetting films. (3) Study of the behavior of the binary alkane-water interface over a wide range of chain lengths and for temperatures near the melting temperature of the bulk alkane. (4) Study of surfactant organization at the liquid- liquid interface in a well defined chemical system as the amplitude of interfacial fluctuations is varied over one to two orders of magnitude. %%% Non-technical The existence of a surface tension is evident by poking a pin into the surface of water. This tension is determined by the free energy required to take molecules from the bulk of the liquid and create a unit area of surface or interface. This energy depends upon the molecular organization at the interface. Many processes that depend upon the interfacial structure occur at liquid-liquid interfaces, such as the transport of molecules across the interface. These processes are important for making new materials, understanding interfacial chemistry, and in biological interfaces such as membranes. Unfortunately, very little experimental information about this interfacial structure is available. We propose to use powerful synchrotron x-ray sources to study this structure at liquid-liquid interfaces. These st udies will include measurements on oil-water interfaces commonly encountered in daily life (and in industrial manufacturing) and also on some exotic interfaces that fluctuate wildly on their own. *** p:\toulouse\abs98