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Study on Non-equilibrium Interface Phenomena by Doppler Rippbn Spectroscopy

多普勒Rippbn光谱研究非平衡界面现象

基本信息

批准号：
13450032
负责人：
SAKAI Keiji
金额：
$ 9.41万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

Langmuir films attract a great physical and industrial interest as a two-dimensional material adsorbed on the liquid surface and liquid-liquid interfaces. The observation of the film structure and the dynamic process of the molecular association is, however, very much difficult since they has the thickness of only one molecular length. The purpose of the study was directed to the development of a novel measurement system of the liquid surface dynamics related to the molecular adsorption/desorption processes. We first demonstrated the possibility of measuring the ripplon power spectrum of the flowing surface by applying the light scattering system to the surface flow cell We successfully observed the asymmetric ripplon spectrum, which is attributed to the flow of the surface; the ripplon propagating along the flow has larger phase velocity than that propagating against it. The asymmetry gives the surface velocity and then it leads to the age of the surface. The dynamic surface process was actually observed for the aqueous solution of the octanoic acid and sodium myristic acid and we found that the surface tension decreases with the aging of the surface. The typical time constants of the surface relaxation are obtained to about several hundreds of ms, which agree well with the theoretical prediction based on the molecular diffusion phenomenon. Further, we tried to obtain the ripplon spectrum within only 10 ms by applying the digital accumulation and the signal processing system for the random signal of te incoherent thermal ripplon. The time resolution of the new system is the world record of the surface measurement at present. The system also provides the surface visco-elasticity besides the surface tension and would give useful information on the condensation of the monomolecular films. The technique would be a powerful and standard tool to investigate the liquid surface physics.

Langmuir膜作为一种吸附在液体表面和液-液界面的二维材料，引起了人们极大的物理和工业兴趣。然而，由于膜的厚度仅为一个分子长度，因此观察膜的结构和分子缔合的动态过程非常困难。本研究的目的是开发一种新的测量系统的液体表面动力学相关的分子吸附/脱附过程。我们首次证明了将光散射系统应用于表面流动池测量流动表面的涟波功率谱的可能性。我们成功地观察到了非对称涟波谱，这归因于表面的流动;沿流沿着传播的涟波相速度大于逆流传播的涟波相速度，这种不对称性使表面速度增大，从而导致了面对辛酸和肉豆蔻酸钠的水溶液进行了动态表面过程的观测，发现表面张力随表面老化而降低。得到的典型的表面弛豫时间常数约为几百ms，这与基于分子扩散现象的理论预测吻合得很好。此外，我们尝试了在10毫秒内获得ripplon谱，通过应用数字积累和信号处理系统的随机信号的非相干热ripplon。新系统的时间分辨率是目前地面测量的世界纪录。该系统除了提供表面张力外，还提供了表面粘弹性，并将提供有关单分子膜凝聚的有用信息。该技术将成为研究液体表面物理的一种强有力的标准工具。