AI 中文总结
研究线性聚索烃在强稳态剪切流中的单分子动力学，用粗粒化布朗动力学模拟。发现奇数聚索烃有稳定坦克履带式运动状态，归因于末端环取向，此行为长时间稳定，还能用于伸展其他分子，有操纵分子的应用潜力。
AI 中文摘要
聚索烃是由通过机械键连接的环状分子组成的机械互锁聚合物。本文利用具有流体动力学相互作用的粗粒化布朗动力学模拟，研究了线性聚索烃在强稳态剪切流中的单分子动力学。我们识别出一种稳定的坦克履带式运动状态，即单个环持续旋转，而整个聚合物保持高度伸展并与流动方向对齐，呈现出通常与拉伸流相关的构象。值得注意的是，坦克履带式运动几乎仅在奇数聚索烃（具有奇数个环的聚索烃）中观察到。我们将这种奇偶效应归因于末端环在流动梯度平面内的取向，它们在其中充当稳定聚合物伸展的锚点，这种构型仅奇数聚索烃可及。此外，我们的模拟和马尔可夫状态模型表明这种动态行为在长时间尺度上保持稳定。最后，我们表明坦克履带式运动的聚索烃可用于在强剪切流中完全伸展其他分子，暗示了这种行为在旋转流中操纵分子的应用前景。
英文摘要
Polycatenanes are mechanically interlocked polymers composed of ring molecules linked through mechanical bonds. Here, we investigate the single-molecule dynamics of linear polycatenanes under strong steady shear flow using coarse-grained Brownian dynamics simulations with hydrodynamic interactions. We identify a stable tank-treading state in which individual rings rotate continuously while the overall polymer remains highly extended and aligned with the flow direction, adopting conformations typically associated with extensional flow. Remarkably, tank-treading is observed almost exclusively in odd polycatenanes, polycatenanes with an odd number of rings. We attribute this odd-even effect to the orientation of the terminal rings within the flow-gradient plane, where they act as anchors that stabilize polymer extension, a configuration accessible only to odd polycatenanes. Furthermore, our simulations and a Markov state model demonstrate that this dynamic behavior remains stable over long timescales. Finally, we show that tank treading polycatenanes can be used to fully extend other molecules in strong shear flow, hinting at applications of this behavior to manipulate molecules in rotational flows.
Comments7 pages + supplementary material, 5 figures, 2 tables
