Branch-Point Motion in Architecturally Complex Polymers: Estimation of Hopping Parameters from Computer Simulations and Experiments
Branch-Point Motion in Architecturally Complex Polymers: Estimation of Hopping Parameters from Computer Simulations and Experiments
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DOI：
10.1021/ma5003936
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发表时间：
2014-05-27
期刊：
影响因子：
5.5
通讯作者：
Das, Chinmay
中科院分区：
文献类型：
--
作者：
Bacova, Petra;Lentzakis, Helen;Das, Chinmay
支化聚合物在管基模型下的驰豫涉及一个参数p(2)，该参数表征了松弛侧臂的跳跃尺寸。根据流变学模型中的假设(例如，关于分支点跳的相关管径)，在文献中，p(2)被设置为从1到1/60的值。通过对不同结构的缠结支化聚合物熔体的大规模分子动力学模拟，以及一组具有许多(类似于30个)侧臂的特征良好的梳状聚合物的实验流变学数据，我们在不同的假设下估计了分层松弛方案中的p(2)的值。模拟和实验都表明，在不同的结构中，考虑主干摩擦和考虑膨胀管中的跳跃提供了一组最一致的跳跃参数。
Relaxation of branched polymers under tube-based models involves a parameter p(2) characterizing the hop size of relaxed side arms. Depending on assumptions made in rheological models (e.g., about the relevant tube diameter for branchpoint hops), p(2) had been set to values varying from 1 to 1/60 in the literature. From large-scale molecular dynamics simulations of melts of entangled branched polymers of different architectures, and from experimental rheological data on a set of well-characterized comb polymers with many (similar to 30) side arms, we estimate the values of p(2) under different assumptions in the hierarchical relaxation scheme. Both the simulations and the experiments show that including the backbone friction and considering hopping in the dilated tube provides the most consistent set of hopping parameters in different architectures.