Shear banding in molecular dynamics of polymer melts.
Shear banding in molecular dynamics of polymer melts.
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DOI：
10.1103/physrevlett.108.028302
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发表时间：
2012-01
影响因子：
8.6
通讯作者：
Jingle Cao;A. E. Likhtman
中科院分区：
文献类型：
--
作者：
Jingle Cao;A. E. Likhtman
为了建立粘弹性流体的本构方程，通常需要均匀的剪切流。然而，在过去的十年中，S.Q.Wang 及其同事证明，一些缠结的聚合物并不像通常假设的那样以均匀的剪切速率流动，而是选择分离成快速流动区域和慢速流动区域。这种现象称为剪切带，会导致流动不稳定，并且原则上在发生这种现象时会使所有流变测量失效。在这封信中，我们报告了在缠结聚合物熔体的分子动力学模拟中剪切带的首次观察。我们表明，我们的观察结果与菲尔丁和奥姆斯特德发展的现象学非常一致。我们的研究结果提供了一种验证剪切带经验宏观现象学的简单方法。
In order to establish constitutive equations for a viscoelastic fluid uniform shear flow is usually required. However, in the last 10 years S. Q. Wang and co-workers have demonstrated that some entangled polymers do not flow with the uniform shear rate as usually assumed, but instead choose to separate into fast and slow flowing regions. This phenomenon, known as shear banding, causes flow instabilities and in principle invalidates all rheological measurements when it occurs. In this Letter we report the first observation of shear banding in molecular dynamics simulations of entangled polymer melts. We show that our observations are in a very good agreement with the phenomenology developed by Fielding and Olmsted. Our findings provide a simple way of validating the empirical macroscopic phenomenology of shear banding.