Ultrastructural Studies of Polymers

这项研究涉及聚合物材料研究的两个领域(1)嵌段共聚物的相变、形态和性质；(2)结晶聚合物的高分辨率电子显微镜(HREM)。第一个领域涉及到关于有序-无序转变和有序-有序转变的整齐线型和星型两嵌段共聚物以及嵌段共聚物/均聚物共混物的详细研究。重点是了解控制相形态和稳定性的分子参数。我们将考察这些模型有序微复合材料的小应变和特别是大应变的力学行为，并将其与微区形态随变形程度的变化相关联。HREM中的这个词将侧重于理解柔性链折叠晶体中的链堆积的细节，特别是关于链排列反映晶体生长的基本信息的区域(初级核、孪生边界、重入生长前沿)。主要研究技术有透射电子显微镜衍射法、小角X射线散射法、数字图像分析法、表面计算机图形学和力学测试等。本研究的目的是为了对结构-性质关系有一个基本的认识，为材料的开发和性能的改善提供依据。

This research deals with two areas of polymer materials research (1) phase transitions, morphology, and properties of block copolymers; and (2) high-resolution electron microscopy (HREM) of crystalline polymers. The first area involves the detailed study of neat linear and star diblock copolymers and block copolymer/homopolymer blends as concerns order-disorder transitions and order-order transitions. Emphasis will be placed on understanding the molecular parameters which govern phase morphology and stability. Both small and especially large-strain mechanical behavior of these model ordered microcomposites will be examined and related to the evolution of domain morphology with extent of deformation. The word in HREM will focus on understanding the details of chain packing in flexible chain-folded crystals particularly as regards regions where the chain arrangement reflects fundamental information on crystal growth (primary nucleus, twin boundaries, reentrant growth fronts). The main investigative techniques are transmission electron microscopy diffraction, small-angle x-ray scattering, digital image analysis, computer graphics of surfaces and mechanical testing. The goal of the research is to contribute to the basic understanding of structure-property relationships which can provide a basis for development of materials and improvement of their properties.