INSA de Lyon, Université de Lyon, MATEIS, UMR CNRS 5510, 69621 Villeurbanne, France.
Phys Rev E. 2017 Nov;96(5-1):052502. doi: 10.1103/PhysRevE.96.052502. Epub 2017 Nov 27.
The ability of a simple coarse-grained finite-extensible nonlinear elastic (FENE) Lennard-Jones (LJ) polymer model to be crystallized is investigated by molecular dynamics simulations. The optimal FENE Lennard-Jones parameter combinations (ratio between FENE and LJ equilibrium distances) and the optimal lattice parameters are calculated for five different perfect crystallite structures: simple tetragonal, body-centered tetragonal, body-centered orthorhombic, hexagonal primitive, and hexagonal close packed. It was found that the most energetically favorable structure is the body-centered orthorhombic. Starting with an equilibrated polymer liquid and with the optimal parameters found for the body-centered orthorhombic, an isothermal treatment led to the formation of large lamellar crystallites with a typical chain topology: folded, loop, and tie chains, and with a crystallinity of about 60%-70%, similar to real semicrystalline polymers. This simple coarse-grained Lennard-Jones model provides a qualitative tool to study semicrystalline microstructures for polymers.
通过分子动力学模拟研究了简单粗粒的有限可伸缩非线性弹性（FENE）Lennard-Jones（LJ）聚合物模型的结晶能力。计算了五种不同完美晶体结构的最佳 FENE Lennard-Jones 参数组合（FENE 和 LJ 平衡距离之比）和最佳晶格参数：简单四方、体心四方、体心正交、六方原始和六方密堆积。结果发现，最具能量优势的结构是体心正交。从平衡的聚合物液体开始，使用体心正交的最佳参数，等温处理导致形成具有典型链拓扑结构的大层状晶体：折叠链、环链和系链，结晶度约为 60%-70%，类似于真实的半结晶聚合物。这种简单的粗粒 Lennard-Jones 模型为研究聚合物的半结晶微观结构提供了一种定性工具。
