Structure Control of Polymeric Materials using Magnetic Fields

本项目主要研究了（1）磁取向机理，（2）利用磁场制备新材料，（3）磁取向新方法，并对Re（1）磁取向嵌段共聚物微相结构进行了研究。结果发现，一个圆柱体和薄片结构下的磁场对齐。各种可能的机制进行了检查，最后得出结论，这是最有可能的形状各向异性是一个主要因素的磁对准。聚丙烯在超临界二氧化碳中结晶时发生了磁取向，Re（2），在磁场作用下，聚丙烯与成核剂一起形成了取向良好的透明膜。此外，液晶嵌段共聚物表现出透明且取向良好的膜。这两种情况表明，磁取向薄膜的透明性和取向性的折衷在本研究中已经被克服。Re（3），我们成功地利用特殊的动态磁场实现了双轴晶体的三维取向。利用调幅或调频磁场实现悬浮在液体介质中的微晶的三维精确排列。这种新技术提供了一种创新的方法，从粉末制造伪单晶。

In this project, we focused on (1) mechanism of magnetic alignment, (2) fabrication of new materials using magneticfield, (3) novel methods of magnetic alignment.Re (1), magnetic alignment of microphase structure of block copolymers was studied. It was found that a cylinder and lamella structures align under magnetic fields. Various possible mechanisms were examined to finally conclude that it is most possible that shape anisotropy is a main factor for the magnetic alignment. Polypropylene underwent magnetic alignment when it was crystallized under supercritical carbon dioxide.Re (2), Polypropylene formed a well-aligned transparent film when treated with nucleating agents under a magnetic field. Also, a liquid crystalline block copolymer exhibited a transparent and well-aligned film. These two cases indicate that the trade-off of transparency and alignment in magnetically aligned films has been overcome in the present research.Re (3), we have succeeded in the 3-dimensional alignment of biaxial crystals using a special dynamic magnetic field. Amplitude or frequency modulated magnetic field was used to achieve the 3-D precise alignment of crystallites suspended in a liquid medium. This novel technique provides an innovative method to fabricate a pseudo-single crystal from powder.