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arXiv 1108.0640cond-mat.soft
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模拟双螺旋Polymer的聚集动力学

The Aggregation Kinetics of a Simulated Telechelic Polymer

Mark Wilson, Avinoam Rabinovitch, Arlette R. C. Baljon

摘要:

我们研究了一种模拟遥爪聚合物凝胶的聚集动力学。在混合分子动力学(MD)/ Monte Carlo(MC)算法中,缔合端基聚集体的形成和断裂遵循MC规则,而聚合物在空间中的位置则由MD决定。因此,聚集体大小在每个时间步长都发生变化。为了描述这种聚集过程,我们采用主方程。它们根据反应速率定义了一定大小的聚集体数量的变化。这些反应速率表明两个聚集体结合形成一个大的聚集体或一个大的聚集体分裂成两个较小部分的可能性。反应速率是从温度范围的模拟中获得的。我们的研究结果表明,速率不仅是温度依赖性的,但也参与反应的聚集体的大小的函数。使用测得的速率,解决方案的主方程被证明是稳定的,并在协议的骨料粒度分布,直接从模拟数据。此外,我们显示了如何在这些速率的温度引起的变化引起所观察到的变化的聚集体分布特征的溶胶-凝胶转变。

英文摘要:

We investigate the aggregation kinetics of a simulated telechelic polymer gel. In the hybrid Molecular Dynamics (MD) / Monte Carlo (MC) algorithm, aggregates of associating end groups form and break according to MC rules, while the position of the polymers in space is dictated by MD. As a result, the aggregate sizes change every time step. In order to describe this aggregation process, we employ master equations. They define changes in the number of aggregates of a certain size in terms of reaction rates. These reaction rates indicate the likelihood that two aggregates combine to form a large one, or that a large aggregate splits into two smaller parts. The reaction rates are obtained from the simulations for a range of temperatures. Our results indicate that the rates are not only temperature dependent, but also a function of the sizes of the aggregates involved in the reaction. Using the measured rates, solutions to the master equations are shown to be stable and in agreement with the aggregate size distribution, as obtained directly from simulation data. Furthermore, we show how temperature induced variations in these rates give rise to the observed changes in the aggregate distribution that characterizes the sol-gel transition.

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