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Investigation of relationship between flow pattern and phase separation structure in a liquid mixture layer using EHD convecttion

使用 EHD 对流研究液体混合物层中流动模式和相分离结构之间的关系

基本信息

批准号：
14550732
负责人：
HOZAWA Mitsunori
金额：
$ 1.92万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14550732/
关键词：
EHD convection Polymer blend Phase separation In-situ observation Numerical simulation 直流電場クエンチ

项目摘要

We have investigated the relationship between the flow pattern based on electrohydrodynamic (EHD) convection and phase separation structure in a polymer blend film. In the present study, the solvent evaporation and thermal quench of polymer blend solutions were adopted to induce the phase separation in the film.In the former method, we have investigated the effect of EHD convection on the domain structure in a polystyrene (PS)/polyvinylacetate (PVA) blend film to demonstrate the feasibility of using the EHD effect as a means of mixing and morphology control in a polymer blend film. Here, polymers-toluene solutions were spread on a glass substrate with patterned electrodes to apply a dc electric field, and well-defined structures of EHD convection were formed in the polymer solutions. As a result, regular patterns were formed in the PS/PVA polymer blend him in which PVA-rich domains were confined within each unit of patterned electrodes, i.e.,between positive and negative electrodes, at an appropriate electric voltage. Also, it was demonstrated that such novel morphology are not due to the wetting/dewetting effect of polymer components to the Pt electrodes deposited on the glass substrate, by experiments with a SiO_2-covered substrate.In the later case, since we had some problems in the experimental apparatus and procedure, unfortunately we could not obtain the available results.In addition, we have developed the numerical simulation code of the phase separation based on the Cahn-Hilliard model with a hydrodynamic effect, and then clarified the effects of the capillary force, gravity force and temperature gradient on the phase separation structure.

研究了聚合物共混膜中基于电流体对流的流型与相分离结构之间的关系。在本研究中，我们利用聚合物共混溶液的溶剂挥发和热淬灭来诱导膜中的相分离。在前一种方法中，我们研究了EHD对流对聚苯乙烯(PS)/聚醋酸乙烯(PVA)共混膜中电晕结构的影响，以论证将EHD效应作为聚合物共混膜中混合和形态控制的一种手段的可行性。在这里，聚合物-甲苯溶液被铺展在带有图案电极的玻璃基板上，以施加直流电场，并且在聚合物溶液中形成了明确的EHD对流结构。结果，在PS/PVA聚合物共混物中形成了规则的图案，其中富含PVA的区域被限制在每个图案化电极单元内，即在适当的电压下，在正负电极之间。此外，通过对SiO_2覆盖的衬底的实验，证明了这种新的形貌并不是由于聚合物组分对沉积在玻璃衬底上的铂电极的润湿/去湿作用所致。在后者的情况下，由于我们在实验装置和程序上存在一些问题，我们无法得到有效的结果。此外，我们还开发了基于具有流体力学效应的Cahn-Hilliard模型的相分离的数值模拟程序，并阐明了毛细作用力、重力和温度梯度对相分离结构的影响。