The structure and dynamic properties of polymers at interfaces

聚合物与其环境之间以及多相聚合物材料中不同组分之间的界面，在宏观的最终用途和加工行为中起着重要作用，如：晶体含量、形态和级配；强度：复合材料的强度；流动下的滑移和生产速度限制特征，如表面断裂或模具流口水。虽然人们对聚合物的表面和界面性质了解很多，但缺乏有关聚合物分子结构、局部结构、组成和界面动态性质以及宏观行为的详细模型。在这项工作中，我们将提供所需的分子水平的理解，这将推动复杂，定量和现实模型的发展。我们将重点关注两种现象，聚合物的表面诱导结晶和聚合物熔体在流动下的滑移，这两种现象都是界面链动力学的表现，主要由链的长度、结构和表面上的吸附决定。

Interfaces, between polymers and their environment and between different constituents in a multiphase polymeric material, play a significant role in macroscopic end-use and processing behaviors such as: the crystalline content, morphology and grading; the strength of a composite material; slip under flow and production rate-limiting features such as surface fracture or die drool. While much is known about the surface and interfacial properties of polymers, there is a lack of detailed models relating the molecular structure of the polymer, its local structure, composition and dynamic properties at the interface and the macroscopic behaviors. In this work we will provide the required molecular level understanding that will drive the development of sophisticated, quantitative and realistic models. We will focus on two phenomena, surface induced crystallization of polymers and slip of polymer melts under flow, that are both manifestations of interfacial chain dynamics primarily determined by chain length, architecture and adsorption on a surface.