Diffusion in Polymer Melts

前向反冲光谱法（FRES）将用于确定 氘代聚合物的浓度-深度分布 扩散到未氘化的核中，反之亦然 的重要性 分子拓扑学将通过研究 具有不同臂数的聚苯乙烯（PS）星扩散到 矩阵由以下组成：各种线性PS 分子量，PS微凝胶和γ-辐射交联 PS星星 结果将与当前的理论进行比较 矩阵独立和矩阵依赖的扩散 星 将开始进行实验，以跟踪 聚苯乙烯和聚（乙烯基吡啶）的嵌段共聚物， 嵌段共聚物基体形态的确定作用 扩散的矩阵。 这些实验将 解释为小块的捕获， 这个区块的结构。 在可混溶的聚合物共混物中， 重点将放在确定示踪剂扩散 二元聚合物共混物中两组分的行为， 确定互扩散系数的增强 由于自由能中的平方梯度项。 测量 的相互扩散系数也将允许一个敏感的 测定共混物的负Flory参数。 最后，将启动实验来测量 大分子沿着表面，即，在二维空间里。 的 所有这些实验的结果将被解释为 当前理论

Forward recoil spectrometry (FRES) will be used to determine the concentration versus depth profiles of deuterated polymers diffusing into undeuterated ones or vice versa. The importance of molecular topology will be explored by investigating the diffusion of polystyrene (PS) stars with various arm numbers into matrices consisting of the following: linear PS of various molecular weights, PS microgels and gamma-irradiation crosslinked PS, and PS stars. Results will be compared with current theories of the matrix-independent and matrix-dependent diffusion of stars. Experiments will be initiated to follow the diffusion of block copolymers of polystyrene and poly(vinylpyridine) into block copolymer matrices to determine the role of the morphology of the matrix on the diffusion. These experiments will be interpreted in terms of the trapping of the minor block by the domain structure of this block. In miscible polymer blends, emphasis will be placed on determining the tracer diffusion behavior of the two components in binary polymer blends and on determining the enhancement of the mutual diffusion coefficient due to the square gradient term in the free energy. Measurements of the mutual diffusion coefficient will also permit a sensitive determination of the negative Flory parameter for the blend. Finally experiments will be initiated to measure the diffusion of macromolecules along surfaces, i.e., in two dimensions. The results of all these experiments will be interpreted in terms of current theory.