聚乙烯分子热运动辅助电子迁移行为的研究

项目名称： 聚乙烯分子热运动辅助电子迁移行为的研究

项目编号： No.51507125

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 电工技术

项目作者： 王洋

作者单位： 西安交通大学

项目金额： 20万元

中文摘要： 绝缘材料内部电荷的跃迁行为关系到其绝大部分介电性能，是绝缘领域长期以来研究的基础难题，也是制约我们进一步了解并改善其绝缘性能的瓶颈。聚乙烯是一种结构简单且应用广泛的绝缘材料，其介电性能一直都是电工学科的研究热点。尽管大量的实验定性研究了其内部电荷的总体规律，但对于电荷在聚乙烯分子结构内的输运情况仍知之甚少。本文将采用分子模拟的方法，利用半经典的理论算法，自主编程研究多种形态结构下、聚乙烯分子热运动辅助电子的迁移行为，进而揭示其电子的输运特性、结构内部的陷阱特性以及电子输运与分子结构的相互作用；并将模拟结果与实验结果进行对比分析，揭示多种实验现象的背后机理。通过本项目的研究，将为进一步理解高分子材料聚集态结构和介电性能的关系、研发具有更高介电性能的新型材料提供有力的理论支撑。

中文关键词： 陷阱；介电特性；；分子模拟；电子跃迁；空间电荷

英文摘要： Electron trapping (carrier localisation) and transport processes are of fundamental interest in a variety of research fields, such as, electrical engineering. Electron transport in polymers is relating to most of its dielectric properties, it has become one of the most basic but challenging problem for researchers. Polyethylene is one of the simplest but most important organic insulators which have been widely used in high-voltage cables, study on its dielectric properties is a one of the hotspot for engineers and scientists. Despite a vast literature concerned with the experimental characterization of its electrical properties, very little is known about the details of the electrical behavior of this material, especially at the molecular level. Here we use a semi-empirical simulation method to study electron transfer behavior assisted by thermal motion of molecules in polyethylene, in order to investigate the electron trapping and transport properties as well as the interactions between molecule thermal motion and electron transition. Moreover, we use our simulation results to explain relative experimental phenomenon. An understanding of the mechanisms of charge trapping and transport in these insulators and how such processes are affected by local physical structures and chemical impurities may help us to further develop its insulating properties.

英文关键词： traps;dielectric properties;molecular simulation;electron transfer;space charge