Wu Zhenghao, Alberti Simon A N, Schneider Jurek, Müller-Plathe Florian
Technical University of Darmstadt, Eduard-Zintl-Institute for Inorganic and Physical Chemistry and Profile Area Thermofluids and Interfaces, Alarich-Weiss-Strasse 8, D-64287 Darmstadt, Germany.
J Phys Condens Matter. 2021 May 13;33(24). doi: 10.1088/1361-648X/abef25.
We analyse the knotting behaviour of linear polymer melts in two types of soft-core models, namely dissipative-particle dynamics and hybrid-particle-field models, as well as their variants with slip-springs which are added to recover entangled polymer dynamics. The probability to form knots is found drastically higher in the hybrid-particle-field model compared to its parent hard-core molecular dynamics model. By comparing the knottedness in dissipative-particle dynamics and hybrid-particle-field models with and without slip-springs, we find the impact of slip-springs on the knotting properties to be negligible. As a dynamic property, we measure the characteristic time of knot formation and destruction, and find it to be (i) of the same order as single-monomer motion and (ii) independent of the chain length in all soft-core models. Knots are therefore formed and destroyed predominantly by the unphysical chain crossing. This work demonstrates that the addition of slip-springs does not alter the knotting behaviour, and it provides a general understanding of knotted structures in these two soft-core models of polymer melts.
我们分析了线性聚合物熔体在两种软核模型中的缠结行为，即耗散粒子动力学模型和混合粒子场模型，以及它们添加了滑移弹簧以恢复缠结聚合物动力学的变体模型。结果发现，与原始硬核分子动力学模型相比，混合粒子场模型中形成结的概率要高得多。通过比较有和没有滑移弹簧的耗散粒子动力学模型与混合粒子场模型中的打结情况，我们发现滑移弹簧对打结特性的影响可以忽略不计。作为一种动态特性，我们测量了结形成和破坏的特征时间，发现它（i）与单链节运动的时间尺度相同，并且（ii）在所有软核模型中均与链长无关。因此，结主要是通过非物理的链交叉形成和破坏的。这项工作表明，添加滑移弹簧不会改变打结行为，并为这两种聚合物熔体软核模型中的打结结构提供了一个总体认识。
