Brachiation of a polymer chain in the presence of a dynamic network
Brachiation of a polymer chain in the presence of a dynamic network
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DOI：
10.1103/physreve.102.020501
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发表时间：
2020-08-06
影响因子：
2.4
通讯作者：
Spakowitz, Andrew J.
中科院分区：
文献类型：
--
作者：
Cai, Pamela C.;Krajina, Brad A.;Spakowitz, Andrew J.
物理交联凝胶的粘弹性行为涉及一系列分子松弛过程，其在单链水平涉及链经历通过网络的瞬时手-手运动。我们开发了一个自洽的理论来描述瞬态关联的聚合物溶液，捕捉这些复杂的动态。单个聚合物链瞬时结合到粘弹性背景，粘弹性背景代表由周围聚合物链形成的聚合物网络。粘弹性背景在运动方程中描述为记忆核，其基于来自链本身的预测流变行为自洽地确定。记忆内核的解决方案被翻译成流变学预测的复数模量在很宽的频率范围内捕捉的物理凝胶的时间依赖性的行为。使用损耗角正切的预测，相图显示动态缔合亲和力的聚合物的溶胶-凝胶转变。该理论为设计具有目标流变性能的缔合凝胶和超分子组装体提供了一个预测性的分子水平框架。
The viscoelastic behavior of a physically crosslinked gel involves a spectrum of molecular relaxation processes, which at the single-chain level involve the chain undergoing transient hand-to-hand motion through the network. We develop a self-consistent theory for describing transiently associating polymer solutions that captures these complex dynamics. A single polymer chain transiently binds to a viscoelastic background that represents the polymer network formed by surrounding polymer chains. The viscoelastic background is described in the equation of motion as a memory kernel, which is self-consistently determined based on the predicted rheological behavior from the chain itself. The solution to the memory kernel is translated into rheological predictions of the complex modulus over a wide range of frequencies to capture the time-dependent behavior of a physical gel. Using the loss tangent predictions, a phase diagram is shown for the sol-gel transition of polymers with dynamic association affinities. This theory provides a predictive, molecular-level framework for the design of associating gels and supramolecular assemblies with targeted rheological properties.