Subdiffusive motion of a polymer composed of subdiffusive monomers.
Subdiffusive motion of a polymer composed of subdiffusive monomers.
复制标题
由亚延伸单体组成的聚合物的延伸运动。
DOI：
10.1103/physreve.82.011913
复制
发表时间：
2010-07
期刊：
影响因子：
--
通讯作者：
Spakowitz AJ
中科院分区：
文献类型：
--
作者：
Weber SC;Theriot JA;Spakowitz AJ
我们使用布朗动力学模拟和分析理论来研究聚合物次扩散运动的物理原理。对单个圆形聚合物的模拟表明，即使在强约束下，弹性劳斯模式的弛豫也主导着单体运动。因此，我们将两个反常扩散模型纳入聚合物动力学劳斯模型的理论框架中。首先，聚合物被认为在粘弹性流体内移动，其中单体经历由分数布朗运动描述的摩擦记忆。其次，我们根据连续时间随机游走模型检查其单体遭受随机暂停事件的聚合物。我们推导出聚合物内单体均方位移的比例定律以及速度自相关函数。无论次扩散机制如何，颗粒都表现出相同的整体平均行为，与粒子不同，次扩散单体运动会导致聚合物的行为发生广泛变化，具体取决于单体次扩散的根本原因。我们的结果可以直接应用于实验，作为确定异常次扩散聚合物动力学的主要物理机制的诊断工具。
We use Brownian dynamics simulations and analytical theory to investigate the physical principles underlying subdiffusive motion of a polymer. Simulations of a single circular polymer reveal that relaxation of the elastic Rouse modes dominates monomer motion, even under strong confinement. Thus, we incorporate two anomalous diffusion models into the theoretical framework of the Rouse model for polymer dynamics. First, a polymer is considered moving within a viscoelastic fluid, in which monomers experience frictional memory described by fractional Brownian motion. Second, we examine a polymer whose monomers are subjected to random pausing events according to the continuous time random walk model. We derive scaling laws for the mean square displacement of a monomer within a polymer, as well as the velocity autocorrelation function. Unlike particles, which exhibit the same ensemble-averaged behavior regardless of subdiffusive mechanism, subdiffusive monomer motion leads to widely varying behavior for a polymer depending on the root cause of the monomer subdiffusion. Our results can be applied directly to experiments as diagnostic tools for determining the dominant physical mechanism underlying anomalous subdiffusive polymer dynamics.