Molecular dynamics simulation of the response of bi-disperse polyelectrolyte brushes to external electric fields  

作　　者：张芬 丁欢达 段超 赵双良 童朝晖 

机构地区：[1]Department of Physics, Ningbo University [2]College of Chemical Engineering, East China University of Science and Technology

出　　处：《Chinese Physics B》2017年第8期521-528,共8页中国物理B（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant No.21374052)

摘　　要：Langevin dynamics simulations have been performed to investigate the response of bi-disperse and strong polyacid chains grafted on an electrode to electric fields generated by opposite surface charges on the polyelectrolyte （PE）-grafted electrode and a second parallel electrode. Simulation results clearly show that, under a negative external electric field, the longer grafted PE chains are more strongly stretched than the shorter ones in terms of the relative change in their respective brush heights. Whereas under a positive external electric field, the grafted shorter chains collapse more significantly than the longer ones. It was found that, under a positive external electric field, the magnitude of the total electric force acting on one shorter PE chain is larger than that on one longer PE chain, or vice versa. The effects of smeared and discrete charge distributions of grafted PE chains on the response of PE brushes to external electric fields were also examined.Langevin dynamics simulations have been performed to investigate the response of bi-disperse and strong polyacid chains grafted on an electrode to electric fields generated by opposite surface charges on the polyelectrolyte （PE）-grafted electrode and a second parallel electrode. Simulation results clearly show that, under a negative external electric field, the longer grafted PE chains are more strongly stretched than the shorter ones in terms of the relative change in their respective brush heights. Whereas under a positive external electric field, the grafted shorter chains collapse more significantly than the longer ones. It was found that, under a positive external electric field, the magnitude of the total electric force acting on one shorter PE chain is larger than that on one longer PE chain, or vice versa. The effects of smeared and discrete charge distributions of grafted PE chains on the response of PE brushes to external electric fields were also examined.

关 键 词：polyelectrolyte brushes electric fields POLYDISPERSITY molecular dynamics 

分 类 号：O631.23[理学—高分子化学]