STABILITY OF THE TWO-PHASE COEXISTENCE AND THE STRUCTURE OF PHASE BOUNDARIES NEAR THE FIRST-ORDER PHASE TRANSITION

两相共存的稳定性和一阶相变附近的相界结构

基本信息

批准号：
05640437
负责人：
HIROTSU Shunsuke
金额：
$ 1.34万
依托单位：
TOKYO INSTITUTE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05640437/
关键词：
Polymer gels Phase transition Phase equilibria Domein boundary Phase separation Gel water Viscoelasticity Coherent solid ゲル体積相転移分域構造高分子物理学相境界パターン形成 2相共存領域

项目摘要

Summary of Research ResultsOn the experimental side, the behavior of domain boundaries in a transition region of gels, and formation of peculiar cellular patterns inside gels embedded in a mixed solvent have been investigated in detail. On the theoretical side, on the other hand, behavior of gel water at the volume phase transition has been analyzed in terms of the experimental data and the phenomenological considerations.(1)Realization of the tri-phasic equilibrium and the temperature behavior of domain boundaries.Fast and precise measurements of the movement of domain boundaries were made possible by requires higher magnification of a microscope to observe the detailed behavior of the domain. Because an objective lense of smaller working distance had to be used, temperature regulation of the sample had become more difficult. We overcame this difficulty by improving the temperature controller as well as the sample holder. It has been confirmed by this experiment that the more advanced … More theoretical considerations than the previous phenomenological one is needed to understand fully the volume phase transition of gels.(2)Observation of the peculiar cellular pattern at the phase separation of gels.It was first demonstrated that, a characteristic cellular pattern developls when the solvent outside the N-isopropylacrylamide gel is changed from pure water to water-ethanol mixture. The fibers constituting this pattern have been found to be birefringent, which suggests that the aggregates has some sort of crystalline order. It is also deduced that NIPA chains are fairly rigid.(3)Behavior of gel water at the volume phase transition.A most significant result emerged from this year's study is that the real volume phase transition occurs in a fairly different fashion from the model predicted by the coventiona Flory's theory. Combining various experimental facts accumulated so far, it has become evident that the shrunken phase of gel does not contain free water, and some kind of ordered structure is present, which is made up from bound water molecules and polymer chains. This fact is important because even a gel made from homopolymer and pure water has some kind of secondary or tertially structure, and thus can be regarded as a model system of much more complex biopolymer systems. Less

研究结果的摘要嵌入了混合溶剂中的凝胶内部的经验模式，已被详细介绍，另一方面，凝胶水在体积过渡时的行为已被实验数据和现象学结构。必须使用域边界的快速和精确的测量域的构造。持有人。与以前的渗透相比，它已经被更先进的理解了已经发现构成这种模式是双重的，这表明聚集体具有晶体相变的一种。到目前为止，Coveninga flory的范围已经变得很明显，凝胶的缩水相位不包含自由水，这是UTER分子和聚合物链，这很重要。。