Slowing Down of Ring Polymer Diffusion Caused by Inter-Ring Threading
Slowing Down of Ring Polymer Diffusion Caused by Inter-Ring Threading
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DOI：
10.1002/marc.201400713
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发表时间：
2015-06-01
影响因子：
4.6
通讯作者：
Jung, YounJoon
中科院分区：
文献类型：
--
作者：
Lee, Eunsang;Kim, Soree;Jung, YounJoon
长环聚合物在熔体中的扩散比其内部结构的重组慢得多。虽然在长环聚合物中没有观察到缠结的直接证据，但与线性聚合物熔体不同，环之间的螺纹被怀疑是环聚合物扩散减慢的主要原因。然而，由于两个环没有链端，因此难以限定两个环之间的螺纹构造。在这项工作中，通过使用分子动力学模拟和应用一种新的分析方法，环状聚合物的线程动力学的证据。模拟结果进行了分析的持久性和交换时间，已被证明是有用的研究玻璃态系统的非均相动力学的统计。结果表明，环状聚合物熔体的穿流时间随聚合度的增加比线型聚合物熔体的快。这表明螺纹环聚合物不能扩散，直到发生脱螺纹事件，这导致环聚合物扩散减慢。
Diffusion of long ring polymers in a melt is much slower than the reorganization of their internal structures. While direct evidence for entanglements has not been observed in the long ring polymers unlike linear polymer melts, threading between the rings is suspected to be the main reason for slowing down of ring polymer diffusion. It is, however, difficult to define the threading configuration between two rings because the rings have no chain end. In this work, evidence for threading dynamics of ring polymers is presented by using molecular dynamics simulation and applying a novel analysis method. The simulation results are analyzed in terms of the statistics of persistence and exchange times that have proved useful in studying heterogeneous dynamics of glassy systems. It is found that the threading time of ring polymer melts increases more rapidly with the degree of polymerization than that of linear polymer melts. This indicates that threaded ring polymers cannot diffuse until an unthreading event occurs, which results in the slowing down of ring polymer diffusion.