Zhang Guojie, Moreira Livia A, Stuehn Torsten, Daoulas Kostas Ch, Kremer Kurt
Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
Innovation Lab GmbH, Speyerer Strasse 4, 69115 Heidelberg, Germany.
ACS Macro Lett. 2014 Feb 18;3(2):198-203. doi: 10.1021/mz5000015. Epub 2014 Jan 30.
A strategy is developed for generating equilibrated high molecular weight polymer melts described with microscopic detail by sequentially backmapping coarse-grained (CG) configurations. The microscopic test model is generic but retains features like hard excluded volume interactions and realistic melt densities. The microscopic representation is mapped onto a model of soft spheres with fluctuating size, where each sphere represents a microscopic subchain with monomers. By varying , a hierarchy of CG representations at different resolutions is obtained. Within this hierarchy, CG configurations equilibrated with Monte Carlo at low resolution are sequentially fine-grained into CG melts described with higher resolution. A Molecular Dynamics scheme is employed to slowly introduce the microscopic details into the latter. All backmapping steps involve only local polymer relaxation; thus, the computational efficiency of the scheme is independent of molecular weight, being just proportional to system size. To demonstrate the robustness of the approach, microscopic configurations containing up to = 1000 chains with polymerization degrees = 2000 are generated and equilibration is confirmed by monitoring key structural and conformational properties. The extension to much longer chains or branched polymers is straightforward.
通过对粗粒化（CG）构型进行顺序反向映射，开发了一种用于生成具有微观细节描述的平衡高分子量聚合物熔体的策略。微观测试模型是通用的，但保留了诸如硬排斥体积相互作用和实际熔体密度等特征。微观表示被映射到具有波动大小的软球模型上，其中每个球代表一个具有单体的微观子链。通过改变，获得了不同分辨率下的CG表示层次结构。在这个层次结构中，在低分辨率下用蒙特卡罗方法平衡的CG构型被顺序细化为用更高分辨率描述的CG熔体。采用分子动力学方案将微观细节缓慢引入后者。所有反向映射步骤仅涉及局部聚合物弛豫；因此，该方案的计算效率与分子量无关，仅与系统大小成正比。为了证明该方法的稳健性，生成了包含多达=1000条链且聚合度=2000的微观构型，并通过监测关键结构和构象性质来确认平衡。将其扩展到更长的链或支化聚合物很简单。
