Ring Polymer Dynamics Are Governed by a Coupling between Architecture and Hydrodynamic Interactions
Ring Polymer Dynamics Are Governed by a Coupling between Architecture and Hydrodynamic Interactions
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DOI：
10.1021/acs.macromol.5b02357
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发表时间：
2016-03-08
期刊：
影响因子：
5.5
通讯作者：
Sing, Charles E.
中科院分区：
文献类型：
--
作者：
Hsiao, Kai-Wen;Schroeder, Charles M.;Sing, Charles E.
线性聚合物链在稀溶液流动中的行为已经有了确定的历史。然而，聚合物通常具有更复杂的结构，例如支化、树枝状或环状结构。一个主要的挑战在于了解这些非线性链拓扑结构如何影响非平衡条件下的动力学性质，在稀释和纠缠的解决方案。在这项工作中，我们询问使用模拟，理论和实验相结合的环状聚合物的单链动力学。受Li等人最近实验结果的启发，我们证明了当聚合物被驱离平衡时，结构约束的存在对聚合物的动态性能具有令人惊讶的和显著的影响。环约束导致两种与线性链不同的行为。首先，线圈拉伸过渡发生在较大的值相比，线性链，这是由分子内流体动力学相互作用（HI）和链结构之间的耦合驱动的无量纲流动强度（韦森伯格数）。其次，观察到一个大的环构象的环状聚合物在中间到大韦森伯格数的拉伸流，我们表明，这种开环构象是由分子内HI驱动。我们的研究结果揭示了链结构流体动力学耦合的新范例的出现，这可能与聚合物材料的基于溶液的加工有关，并且可以为精确的基于流动的聚合物构象控制提供新的机会，以指导材料性能。
The behavior of linear polymer chains in dilute solution flows has an established history. Polymers often possess more complex architectures, however, such as branched, dendritic, or ring structures. A major challenge lies in understanding how these nonlinear chain topologies affect the dynamic properties in nonequilibrium conditions, in both dilute and entangled solutions. In this work, we interrogate the single-chain dynamics of ring polymers using a combination of simulation, theory, and experiment. Inspired by recent experimental results by Li et al., we demonstrate that the presence of architectural constraints has surprising and pronounced effects on the dynamic properties of polymers as they are driven out of equilibrium. Ring constraints lead to two behaviors that contrast from linear chains. First, the coil-stretch transition occurs at larger values of the dimensionless flow strength (Weissenberg number) compared to linear chains, which is driven by coupling between intramolecular hydrodynamic interactions (HI) and chain architecture. Second, a large loop conformation is observed for ring polymers in extensional flow at intermediate to large Weissenberg numbers, and we show that this open loop conformation is driven by intramolecular HI. Our results reveal the emergence of new paradigms in chain architecture hydrodynamic coupling that may be relevant for solution-based processing of polymeric materials and could provide new opportunities for precise flow-based polymer conformation control to guide material properties.