Real-Space Analysis of Branch Point Motion in Architecturally Complex Polymers

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• 作者：Petra Ba膷ov谩 ; Angel J. Moreno
• 刊名：Macromolecules
• 出版年：2014
• 出版时间：October 14, 2014
• 年：2014
• 卷：47
• 期：19
• 页码：6955-6963
• 全文大小：527K
• ISSN：1520-5835

文摘

By means of large-scale molecular dynamics simulations, we investigate branch point motion in pure branched polymers and in mixtures of stars and linear chains. We perform a purely geometrical density-based cluster analysis of the branch point trajectories and identify regions of strong localization (traps). Our results demonstrate that the branch point motion can be described as the motion over a network of traps at the time scales corresponding to the reptation regime. Residence times within the traps are broadly distributed, even extending to times much longer than the side-arm relaxation time. The distributions of distances between consecutively visited traps are very similar for all the investigated branched polymers, even though tube dilation is much stronger in the star/linear mixtures than in the pure branched systems. Our analysis suggests that the diffusivity of the branch point introduced by hierarchical models must be understood as a parameter to account for the effective friction associated with the relaxed side arm, more than the description of a hopping process with a precise time scale.