摘要
采用多粒子碰撞动力学与分子动力学相耦合的模拟方法,研究了圆管内环形链的迁移行为和构象性质,并与线形链的结果相比较.模拟结果表明环形链随着流场强度的增加向圆管中心迁移,该现象是流体力学相互作用导致,而非剪切梯度.剔除流体力学相互作用,发现环形链沿流场方向的拉伸程度比含流体力学相互作用时更大.给定流场强度,环形链链长越长,与管壁之间的流体力学相互作用越强,导致其在圆管中心附近出现的概率更高.通过比较相同平衡态尺寸和链长的环形链和线形链在圆管中的迁移行为和构象性质,发现线形链沿流场方向的拉伸比环形链更强,导致其更易向管壁方向发生迁移,因此线形链在圆管中心附近出现的概率低于环形链.
The dynamical and conformational properties of individual ring polymers with different chain lengths are investigated in Poiseuille flow through a tube using a hybrid mesoscale hydrodynamic simulation method, and migration behaviors are compared with those of linear chains. As the flow strength is increased, the ring chains migrate towards the centerline of the tube when the hydrodynamic interactions are included, but towards the tube wall when the hydrodynamic interactions are switched off. By analyzing the radial center-of-mass distribution function and the width of the distribution function of the ring chains, our studies reveal that the migration towards the centerline of the tube should be attributed to the hydrodynamic interactions rather than to the shear gradient in the Poiseuille flow. With the increase of flow intensity, the ring chains stretched more along the flow direction and shrunk smaller along the radial direction, independent of the location of their center-of-mass across the tube.When the hydrodynamic interactions are switched off, the extension along the flow direction and the shrinkage along the radial direction of the ring polymers are more pronounced than those with the hydrodynamic interactions. For a given flow strength, the longer the ring chain is, the eaiser it is to concentrate around the center of the tube due to the stronger hydrodynamic interactions between the chain and the tube wall, and the resulting distribution structure transits from the platform to the bimodal, and finally to the single-peaked with increasing chain length. By comparing the center-of-mass distributions and the structural properties between the ring and linear chains with the same chain length or the equilibrium radius of gyration, our simulation results show that the linear chains exhibit a more stretched conformation along the flow direction than the ring polymer chains, leading to the outward migration with a lower number density in the tube center.
作者
杨镇岳
陈文多
刘立军
陈继忠
Zhen-yue Yang;Wen-duo Chen;Li-jun Liu;Ji-zhong Chen(State Key Laboratory of Polymer Physics and Chemistry,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun 130022;University of Chinese Academy of Sciences,Beijing 100049;School of Materials,Sun Yat-sen University,Guangzhou 510275)
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2019年第11期1239-1248,共10页
Acta Polymerica Sinica
基金
国家自然科学基金(基金号21574134,21774127,21504093,21790342)
中国科学院前沿科学重点项目(项目号QYZDY-SSW-SLH027)资助
关键词
泊肃叶流
环形链
流体力学相互作用
高分子迁移
Poiseuille flow
Ring polymer
Hydrodynamic interactions
Polymer migration
