Liu Li, den Otter Wouter K, Briels Wim J
Department of Information Science and Engineering , Dalian Polytechnic University , Dalian 116034 , China.
Forschungszentrum Jülich, ICS 3 , D-52425 Jülich , Germany.
J Phys Chem B. 2018 Nov 8;122(44):10210-10218. doi: 10.1021/acs.jpcb.8b03104. Epub 2018 Oct 26.
Melts of three-armed star polymers have been simulated using a coarse-grained model parameterized by atomistic simulations of polyethylene. The bonds between the highly coarse-grained, and hence soft, polymer beads are explicitly prevented from crossing by the TWENTANGLEMENT algorithm. The three melts of symmetric stars, differing in the lengths of the arms, are compared against five melts of linear polymers with comparable dimensions to study the impact of branched architecture on self-diffusion and bulk rheological properties. Differently from the power-law relation between the viscosity and molecular mass of linear chains, the star polymers in our simulations follow an exponential mass-viscosity relation and show qualitative agreement with the storage and loss moduli for stars with far longer arms from experiments. The stress relaxation dynamics of the stars are also compared with theoretical analysis in terms of Rouse modes.
使用通过聚乙烯原子模拟参数化的粗粒化模型对三臂星形聚合物熔体进行了模拟。通过TWENTANGLEMENT算法明确防止高度粗粒化（因此较软）的聚合物珠之间的键相互交叉。比较了臂长不同的对称星形的三种熔体与尺寸相当的线性聚合物的五种熔体，以研究支化结构对自扩散和本体流变性能的影响。与线性链的粘度和分子量之间的幂律关系不同，我们模拟中的星形聚合物遵循指数质量-粘度关系，并且与实验中臂长得多的星形的储能模量和损耗模量显示出定性一致性。还根据Rouse模式将星形的应力松弛动力学与理论分析进行了比较。
