Disentanglement of Linear Polymer Chains Toward Unentangled Crystals
Disentanglement of Linear Polymer Chains Toward Unentangled Crystals
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DOI：
10.1021/mz300552x
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发表时间：
2013-01-01
影响因子：
7.015
通讯作者：
Sommer, Jens-Uwe
中科院分区：
文献类型：
--
作者：
Luo, Chuanfu;Sommer, Jens-Uwe
采用大尺度长时间分子动力学模拟和原始路径分析方法研究了高分子长链从熔融态结晶过程中的解缠结现象。在一般情况下，可以观察到两个竞争过程，在冷却过程中的平均缠结长度的缓慢减少所造成的链的硬化和结晶过程中的强烈增加，。在均质和非均质成核中，通过从局部未缠结的片段形成褶皱发生解缠结，并且在结晶后过程（缓慢重组）中继续，特别是在退火期间。熔化后的再缠结过程是缓慢的，并且可能导致加热-再冷却协议（例如自引晶）中的记忆效应。
Large scale and long time molecular dynamics simulations and primitive path analysis are used to investigate the disentanglement of long linear polymer chains during their crystallization from the melt state. In general, two competitive processes, a slow decrease of average entanglement length during cooling caused by stiffening of chains and a strong increase during crystallization, can be observed. In both homogeneous and heterogeneous nucleation, disentanglement occurs via forming folds from locally unentangled segments and continues in postcrystallization processes (slow reorganization), in particular, during annealing. Re-entanglement processes after melting are slow and can lead to memory effects in heating-recooling protocols such as self-seeding.