Ma Mengze, Fu Yao
Department of Aerospace Engineering and Engineering Mechanics, University of Cincinnati, Cincinnati, OH 45221, USA.
Polymers (Basel). 2019 Sep 23;11(10):1546. doi: 10.3390/polym11101546.
Polymerized ionic copolymers have recently evolved as a new class of materials to overcome the limited range of mechanical properties of ionic homopolymers. In this paper, we investigate the structural and mechanical properties of charged ionic homopolymers and di-block copolymers, while using coarse-grained molecular dynamics simulation. Tensile and compressive deformation are applied to the homopolymers and copolymers in the glassy state. The effect of charge ratio and loading direction on the stress-strain behavior are studied. It is found that the electrostatic interactions among charged pairs play major roles, as evidenced by increased Young's modulus and yield strength with charge ratio. Increased charge ratio lead to enhanced stress contribution from both bonding and pairwise (Van der Waals + coulombic) interaction. The increase in the gyration of the radius is observed with increasing charge ratio in homopolymers, yet a reversed tendency is observed in copolymers. Introduced charge pairs leads to an increased randomness in the segmental orientation in copolymers.
聚合离子共聚物最近已发展成为一类新型材料，以克服离子均聚物机械性能范围有限的问题。在本文中，我们使用粗粒度分子动力学模拟研究了带电离子均聚物和二嵌段共聚物的结构和机械性能。对处于玻璃态的均聚物和共聚物施加拉伸和压缩变形。研究了电荷比和加载方向对应力-应变行为的影响。结果发现，带电对之间的静电相互作用起主要作用，这表现为杨氏模量和屈服强度随电荷比增加。电荷比增加导致键合和成对（范德华力+库仑力）相互作用的应力贡献增强。在均聚物中，随着电荷比增加，回转半径增大，但在共聚物中观察到相反的趋势。引入的电荷对导致共聚物链段取向的随机性增加。
