大学物理 ›› 2016, Vol. 35 ›› Issue (11): 45-51.doi: 10.16854/j.cnki.1000-0712.2016.0166

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球形聚电解质刷的自洽场模拟

苏志成,虎 伟   

  1. 北京师范大学物理学系,北京 100875
  • 收稿日期:2013-03-13 修回日期:2016-03-09 出版日期:2016-11-20 发布日期:2016-11-20
  • 作者简介:苏志成(1989— ),男,甘肃平凉人,北京师范大学物理学系2009 级本科生.

Numerical simulation of spherical polyelectrolyte brushes by self-consistent filed theory

SU Zhi cheng,HU Wei   

  1. Department of physics,Beijing Normal University,Beijing 100875,China
  • Received:2013-03-13 Revised:2016-03-09 Online:2016-11-20 Published:2016-11-20

摘要: 利用自洽场理论(self-consistent filed theory,SCFT)研究了聚电解质体系盐浓度、链接枝密度及带电比对球形聚电解质刷相 行为的影响,并和标度理论3 种刷型的标度关系进行了对照.自洽场理论计算结果不仅给出了3 种类型聚电解质刷的行为趋势,而且可以为不同类型重叠区的刷行为提供更多细节信息.离子的密度分布表明体系始终是局部电中性的,加盐刷与中性刷有相似之处,而渗透压刷的接枝链并不是均匀伸展.盐浓度下降时,单体自由端分布移向外层并出现排空区.

关键词: 自洽场理论, 聚电解质, 盐浓度, 接枝密度, 构象

Abstract: A spherical polyelectrolyte brush is studied by self-consistent field theory (SCFT)and the results are compared with predictions from scaling theory.It is shown that the SCFT results give the general trends as well as insight into the crossover regions between different regimes. The density profiles of the polyions and small ions indicate that the systems are locally electroneutral.The salted brush bears characteristics similar to those of a neutral brush.Counter-intuitively,the chains are not uniformly stretched in the osmotic regime.The free-end monomers shift to the outer region and an exclusion zone appears and grows with decreasing of salt concentration.

Key words: SCFT, polyelectrolyte, salt concentration, grafting density, morphology