Dynamics and rheology of ring-linear blend semidilute solutions in extensional flow. Part I: Modeling and molecular simulations
Dynamics and rheology of ring-linear blend semidilute solutions in extensional flow. Part I: Modeling and molecular simulations
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DOI：
10.1122/8.0000221
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发表时间：
2020-11
影响因子：
3.3
通讯作者：
Charles D. Young;Yuecheng Zhou;Charles M. Schroeder;C. Sing
中科院分区：
文献类型：
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作者：
Charles D. Young;Yuecheng Zhou;Charles M. Schroeder;C. Sing
我们使用布朗动力学（BD）模拟和单分子实验研究的拓扑约束和流体动力学相互作用的影响，在重叠浓度的环状线性聚合物共混物的解决方案的动力学和流变学。我们发现模拟和实验之间的协议，在溶液共混物中的环表现出大的构象波动。环的一个亚群在流动的启动时显示出延伸过冲，而其他种群在稳定状态下显示出翻滚和坦克踩踏。环聚合物的波动随着线性聚合物的共混分数的增加而增加，并且在环Weissenberg数WiR 1：5处达到峰值。相反，纯溶液中的线性和环状聚合物在临界线圈拉伸Weissenberg数Wi 1/4 0：5处显示出波动峰值。BD模拟表明，延伸过冲的启动流是由于流动引起的分子间的环状线性聚合物钩，而在稳定状态下的波动主要由分子间的流体动力学相互作用（HI）。这是支持模拟的双分散线性聚合物溶液共混物，这表明类似的趋势，在环和线性聚合物之间的构象动力学与匹配的轮廓长度。与BD模拟相比，单分子实验定量地显示出更大的波动，这可能是因为实验是在具有更强拓扑约束的更高分子量聚合物上进行的。为此，我们已经提前了解的拓扑相互作用和分子间HI的半稀环线性聚合物共混物溶液的动力学的影响。© 2021流变学学会。https://doi.org/10.1122/8.0000221
We use Brownian dynamics (BD) simulations and single molecule experiments to investigate the influence of topological constraints and hydrodynamic interactions on the dynamics and rheology of solutions of ring-linear polymer blends at the overlap concentration. We find agreement between simulation and experiment in which rings in solution blends exhibit large conformational fluctuations. A subpopulation of rings shows extension overshoots in the startup of the flow, and other populations display tumbling and tank-treading at the steady state. Ring polymer fluctuations increase with the blend fraction of linear polymers and are peaked at a ring Weissenberg number WiR 1:5. On the contrary, linear and ring polymers in pure solutions show a peak in fluctuations at the critical coil-stretch Weissenberg number Wi 1⁄4 0:5. BD simulations show that extension overshoots on the startup of the flow are due to flow-induced intermolecular ring-linear polymer hooks, whereas fluctuations at the steady state are dominated by intermolecular hydrodynamic interactions (HIs). This is supported by simulations of bidisperse linear polymer solution blends, which show similar trends in conformational dynamics between rings and linear polymers with a matched contour length. Compared to BD simulations, single molecule experiments show quantitatively larger fluctuations, which could arise because experiments are performed on higher molecular weight polymers with stronger topological constraints. To this end, we have advanced the understanding of the effects of topological interactions and intermolecular HIs on the dynamics of semidilute ring-linear polymer blend solutions. © 2021 The Society of Rheology. https://doi.org/10.1122/8.0000221