论文标题
纠缠聚合物成核的自由化屏障的数值计算
Numerical calculation of free-energy barriers for entangled polymer nucleation
论文作者
论文摘要
使用带有粗粒模型的计算机模拟研究了融化中纠缠聚合物的结晶。使用混合蒙特卡洛模拟使我们能够探测长聚合物链的行为。我们用中心对称局部阶参数鉴定固体样珠，并以相对较高的高温和适应性偏置的窗户式的雨伞采样来计算成核的自由能屏障。我们的结果表明，临界核大小和自由能屏障的高度并不显着取决于聚合物的分子量。但是，成核速率随着分子量的增加而降低。此外，对临界核的组成的分析表明，成核簇的分子内生长对该系统的结晶没有显着贡献。
The crystallisation of entangled polymers from their melt is investigated using computer simulation with a coarse-grained model. Using hybrid Monte Carlo simulations enables us to probe the behaviour of long polymer chains. We identify solid-like beads with a centrosymmetry local order parameter and compute the nucleation free-energy barrier at relatively high supercooling with adaptive-bias windowed umbrella sampling. Our results demonstrate that the critical nucleus sizes and the heights of free-energy barriers do not significantly depend on the molecular weight of the polymer; however, the nucleation rate decreases with increasing molecular weight. Moreover, an analysis of the composition of the critical nucleus suggests that intramolecular growth of the nucleated cluster does not contribute significantly to crystallisation for this system.
