论文标题
链分辨率对流量中隔离聚合物链的布朗动力学模拟的构型和流变预测的影响
Effects of chain resolution on the configurational and rheological predictions from Brownian dynamics simulations of an isolated polymer chain in flow
论文作者
论文摘要
聚合物链的合理准确表示由与杆相连的珠子，或模仿单个kuhn步骤的僵硬，不可扩展的弹簧。由于高计算成本，在典型的应用中使用了粗粒珠子弹簧模型，每个春季都应该取代多个库恩步骤。较早的研究表明，具有不同水平的离散化水平在不同的流量中对稳态的BD仿真预测在很大程度上相似。但是，即使对于稳态也存在微妙的定量差异。在这项研究中，我们对不同程度的链离散化产生的行为差异进行了详细的分析，范围从一个到几百个库恩步骤。我们比较单轴扩展和稳定剪切流的单个链的配置和流变特性的瞬态和稳定行为。我们的分析突出了珠子杆和珠子弹簧模型之间在中间和高流量下获得的差异，尤其是在压力和粘度值中的差异。这样的透彻理解有助于在给定应用中为基础聚合物链提供最佳可能的珠弹簧代表。此外，我们还调查了春季法律违反的限制，即春季可以忠实模仿的库恩步骤的最低数量。
A reasonably accurate representation of a polymer chain is provided by beads connected with rods, or stiff, inextensible springs that mimic a single Kuhn step. Due to high computational cost, coarse-grained bead-spring models are used in typical applications, where each spring is supposed to replace several Kuhn steps. Earlier investigations indicate that the BD simulation predictions of the steady state in different flows, with these different levels of discretization, are largely qualitatively similar. However, subtle quantitative differences exist even for the steady states. In this study, we perform a detailed analysis of the behavioral differences arising out of the varying degrees of chain discretization, ranging from one to several hundred Kuhn steps. We compare the transient and steady behavior of both configuration and rheological properties for a single chain in uniaxial extension and steady shear flow. Our analysis highlights differences, particularly in the stress and viscosity values, obtained at intermediate and high flow rates, between the bead-rod and bead-spring models. Such a thorough understanding helps to provide an estimate of the best possible bead-spring representation for an underlying polymer chain in a given application. Additionally, we also investigate the limit of break-down of the spring laws i.e. the minimum number of Kuhn steps that a spring can mimic faithfully.
