论文标题
在受限聚合物中分离的几何和拓扑纠缠不平衡
Separation of Geometrical and Topological Entanglement in Confined Polymers Driven Out-Of-Equilibrium
论文作者
论文摘要
我们使用布朗动力学模拟和高级拓扑概况方法来表征线性聚合物中局限于纳米通道和周期性压缩的线性聚合物中自我输入的不平衡演变。我们区分了两种主要形式的纠缠,几何和拓扑。后者是通过合适的链末端桥接后检测到的物理结(基本结节)数量来测量的。相反,前者是作为在所有预测下观察时线性链似乎越过自身的平均次数,并且无论物理打结状态如何。我们作品的关键发现是,这两种形式的纠缠是没有耦合的,并以独特的动态发展。虽然几何纠缠通常与压缩 - 延长循环相相,并且主要对其力F敏感,但拓扑度量对环状调制非常敏感,但强烈取决于压缩力F和持续时间k。这些发现可以有助于使用荧光分子示踪剂来解释实验,以跟踪聚合物中的物理结。此外,我们在实验控制的参数空间中确定了最佳区域,在这些参数空间中获得更多/较少的拓扑和几何纠缠;这可能有助于设计具有靶向拓扑的聚合物。
We use Brownian dynamics simulations and advanced topological profiling methods to characterize the out-of-equilibrium evolution of self-entanglement in linear polymers confined into nano-channels and under periodic compression. We distinguish two main forms of entanglement, geometrical and topological. The latter is measured by the number of (essential) crossings of the physical knot detected after a suitable bridging of the chain termini. The former is instead measured as the average number of times a linear chain appears to cross itself when viewed under all projections, and is irrespective of the physical knotted state. The key discovery of our work is that these two forms of entanglement are uncoupled and evolve with distinct dynamics. While geometrical entanglement is typically in phase with the compression-elongation cycles and it is primarily sensitive to its force f, the topological measure is mildly sensitive to cyclic modulation but strongly depends on both compression force f and duration k. The findings could assist the interpretation of experiments using fluorescence molecular tracers to track physical knots in polymers. Furthermore, we identify optimal regions in the experimentally-controllable parameter space in which to obtain more/less topological and geometrical entanglement; this may help designing polymers with targeted topology.