arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1607.04355cond-mat.softcond-mat.mtrl-scicond-mat.stat-mech
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缠结链Polymer液体介观动力学局域化和熵弹性的节段尺度、力级理论

Segment-Scale, Force-Level Theory of Mesoscopic Dynamic Localization and Entropic Elasticity in Entangled Chain Polymer Liquids

Zachary E. Dell, Kenneth S. Schweizer

摘要:

我们开发了一个段尺度,基于力的理论的故障的非纠缠劳斯模型和随后出现的各向同性介观本地化和熵弹性链聚合物液体中的遍历性恢复各向异性爬行运动的情况下。该理论是制定在构象N-动态序参数广义朗之万方程的方法。它是使用场论高斯线程模型的聚合物结构和封闭的普遍方式在链动态二阶矩矩阵的水平。物理思想是,各向同性Rouse模型由于时间持续的分子间接触的动力学出现而失败,所述时间持续的分子间接触由局部链不可交叉性、长程聚合物连接性和链运动的自洽处理以及阻碍它的动态力的综合影响确定。介观局域化长度(管直径)和涌现弹性预测与实验接近定量一致。此外,起始链长的比例与半稀释交叉浓度与一个现实的数值前因子。不同的预测作出各种非对角关联函数,量化的动态本地化的聚合物构象的完整的空间结构。由于局部不可交叉性约束和/或链内结合弹簧被软化,预测管直径膨胀,直到其达到链回转半径,在该点缠结局部化以不连续的方式消失。一个完整的动态相图的破坏介观局域化的构造,这是定性与模拟和聚合的纠缠度的经典概念一致。

英文摘要:

We develop a segment-scale, force-based theory for the breakdown of the unentangled Rouse model and subsequent emergence of isotropic mesoscopic localization and entropic elasticity in chain polymer liquids in the absence of ergodicity-restoring anisotropic reptation motion. The theory is formulated in terms of a conformational N-dynamic-order-parameter Generalized Langevin Equation approach. It is implemented using a field-theoretic Gaussian thread model of polymer structure and closed in a universal manner at the level of the chain dynamic second moment matrix. The physical idea is that the isotropic Rouse model fails due to the dynamical emergence of time-persistent intermolecular contacts determined by the combined influence of local chain uncrossability, long range polymer connectivity and a self-consistent treatment of chain motion and the dynamic forces that hinder it. For long chain melts, the mesoscopic localization length (tube diameter) and emergent elasticity predictions are in near quantitative agreement with experiment. Moreover, the onset chain length scales with the semi-dilute crossover concentration with a realistic numerical prefactor. Distinctive predictions are made for various off-diagonal correlation functions that quantify the full spatial structure of the dynamically localized polymer conformation. As the local uncrossability constraint and/or intrachain bonding spring are softened, the tube diameter is predicted to swell until it reaches the chain radius-of-gyration at which point entanglement localization vanishes in a discontinuous manner. A full dynamic phase diagram for the destruction of mesoscopic localization is constructed, which is qualitatively consistent with simulations and the classical concept of an entanglement degree of polymerization.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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