Molecular Manipulation on Crystal Orientation, Phase Transformation and Stability in Nano-Confined Environments using Block Co-polymers and Blends as Templates

该提案的目标是获得聚合物限制在纳米环境中具有不同的几何形状和尺寸，使用嵌段共聚物和共混物作为模板，以实现聚合物在这些纳米限制空间中的相变过程中的行为的基本理解。 主要研究包括几个重要目标。 首先，将设计和合成一系列新的无定形-结晶嵌段共聚物和共混物（通过与阿克伦大学的合成教授合作）。 在构建这些纳米约束环境的基本思想涉及操纵有序-无序的相形态的转变温度，玻璃化转变温度的无定形块，和结晶温度的结晶块使用不同的化学结构，分子量和形状之间的关系。 这些受限的几何形状的范围可以从相对简单的层状、圆柱形和球形几何形状到复杂的六边形穿孔层、双回转体和反相。 第二，系统的研究薄膜和块状样品中的可结晶块的相取向和结构变化将在不同的结晶温度下在各种受限的几何形状和尺寸内进行。 通过将这些受限样品的结果与相应的非受限聚合物的结果进行比较，可以阐明尺寸和几何形状对相取向和结构的影响。 本研究的第三个目标将集中于基于相尺寸的相稳定性反演的概念。 为此目的，所设计的无定形-结晶嵌段共聚物将需要具有表现出多晶型的可结晶嵌段。 该方法不仅有助于提高对聚合物相结构和相转变的尺寸效应的科学认识，而且为设计具有所需机械、电学、机械性能的新型纳米材料提供了一条途径。和光学特性的不同纳米技术。

The goal of this proposal is to obtain polymers confined in nano-environments with different geometric shapes and sizes using block copolymers and blends as templates to achieve a fundamental understanding of how polymers behave during phase transformations in these nano-confined spaces. The main research includes several important objectives. First, a series of new amorphous-crystalline block copolymers and blends will be designed and synthesized (by collaborating with the synthetic professors at Univ. of Akron). The basic idea in constructing these nano-confined environments involves manipulating the relationships among the order-disorder transition temperature of the phase morphology, the glass transition temperature of the amorphous blocks, and the crystallization temperatures of the crystallizable blocks using different chemical structures, molecular weights, and shapes. These confined geometric shapes may range from relatively simple lamellar, cylindrical, and spherical geometries to complex hexagonal perforated layers, double gyroids, and inverse phases. Second, systematic studies of the phase orientation and structural changes of the crystallizable blocks in thin film and bulk samples will be carried out at different crystallization temperatures within various confined geometric shapes and sizes. By comparing the results from these confined samples with those of their corresponding unconfined polymers, the size and geometry effects on the phase orientations and structures can be elucidated. The third objective of this research will concentrate on the concept of phase stability inversion based on the phase size. For this purpose, the designed amorphous-crystalline block copolymers will need to have crystallizable blocks which exhibit polymorphism. With this approach, a quantitative understanding of the relationship between the size of the phase and the phase stability will be attained.The approach presented in this proposal will not only be valuable by enhancing the scientific understanding of the size effect on polymer phase structures and transformations, it will also provide a gateway in designing novel nano-materials that possess desired mechanical, electrical, and optical properties in different nano-technologies.