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Scanning Ripplon Microscopy

扫描波纹显微镜

基本信息

批准号：
06555019
负责人：
TAKAGI Kenshiro
金额：
$ 6.08万
依托单位：
UNIVERSITY OF TOKYO
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06555019/
关键词：
Ripplon Surface Tension wave Light Scattering Langmuir Film Liquid Surface Physics Two-dimensional Phase Transition Phase Separation リプロンスペクトロスコピー光散乱測定光ヘテロダイン分光法

项目摘要

Langmuir film, a monolayr of molecules expanded on water surface, is important as a material for the LB film which has various industrial applications. The film shows phase transitions among two-dimensional gas, liquid and solid phases, and has attracted also a pure physical interest. In our previous studies we had established "Wide-band ripplon light scattering technique" for a non-contact measurement of ripplon, ie. high-frequency capillary waves thermally excited and propagating on water surface. This technique has been applied for investigating molecular dynamics in the Langmuir films ; local structure of the film, inhomogenuity and state of condensation have been revealed.The purpose of the present study is to develop "a ripplon microscope" by increasing spatial resolution of this light scattering technique and combining it with a surface scanning system. It would be useful for quantitative evaluation of the films by measuring the surface energy and the surface visco-elasticity, the values which sensitively reflect the state of monomolecular layr on water surface. It would provide us with a very effective means for structure analysis of Langmuir films. We also intended to clarify how the function of a LB film is determined by the structure and dynamics of the Langmuir film as its material.In this study we improved the signal processing and the optical system of the technique ; and constructed a surface scanning system. We succeeded in visualizing the surface structure with -10 mum spatial resolution and precision. We applied the new system for studying various effects of two-dimensional physics, including thermal expansion, and phase transitions. These results taught us an interesting fact two-dimensional substances also have critical phenomena as the more familiar three-dimensional ones, and their behavior is described within a framework of the mean field theory.

朗缪尔膜是一种在水面上膨胀的单分子膜，是一种重要的材料，在工业上有着广泛的应用。该薄膜显示了二维气、液、固三相之间的相变，也吸引了纯粹的物理兴趣。在我们以前的研究中，我们已经建立了“宽带涟漪光散射技术”来非接触测量涟漪，即。在水面上热激发和传播的高频毛细波。这项技术已被应用于研究朗缪尔薄膜的分子动力学，揭示了薄膜的局部结构、不均匀性和凝聚状态。本研究的目的是通过提高这种光散射技术的空间分辨率并将其与表面扫描系统相结合来研制“涟漪显微镜”。通过测量表面能和表面粘弹性这两个能灵敏地反映水表面单分子层状态的数值，将有助于对薄膜的定量评价。这将为朗缪尔薄膜的结构分析提供一种非常有效的手段。我们还试图阐明作为其材料的朗缪尔膜的结构和动力学是如何决定其功能的。在本研究中，我们改进了该技术的信号处理和光学系统；并构建了表面扫描系统。我们成功地以-10微米的空间分辨率和精度可视化了表面结构。我们将新系统应用于研究二维物理的各种效应，包括热膨胀和相变。这些结果告诉我们一个有趣的事实，二维物质和更常见的三维物质一样也有临界现象，它们的行为是在平均场理论的框架内描述的。