Using molecular dynamics simulations, the flexible ring polyelectrolyte chains tethered to a planar substrate and immersed in good solvents are investigated systematically. Two sets of simulations are performed to explore the effects of grafting density and charge fraction, respectively. Both the monovalent and trivalent counterions are considered. The height of the brush H follows a scaling relation with grafting density (~ σ g ν ) and charge fraction (~ f ν ). The values of the exponents are different from those of the linear counterparts. Through a careful analysis on the distributions of monomers and counterions, pair correlation functions of monomer-monomer and monomer-counterion, as well as the fractions of trivalent counterions in four states, the equilibrium structures of the ring PE brushes are examined in detail. Furthermore, a brief comparison with the ‘equivalent’ linear brush is carried out. Also, our results can serve as a guide for improving the performance of ring polyelectrolyte brushes as unique surface modifiers. Graphical abstract .

中文翻译：

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接枝密度和电荷分数对环状聚电解质刷性能的影响：分子动力学模拟研究

使用分子动力学模拟，系统地研究了拴在平面基材上并浸入良好溶剂中的柔性环聚电解质链。执行两组模拟以分别探索接枝密度和电荷分数的影响。考虑了单价和三价反离子。刷子 H 的高度与接枝密度 (~ σ g ν ) 和电荷分数 (~ f ν ) 成比例关系。指数的值与线性对应物的值不同。通过对单体和抗衡离子的分布、单体-单体和单体-抗衡离子的配对相关函数以及四种状态下三价抗衡离子的分数的仔细分析，详细研究了环形PE刷的平衡结构。此外，进行了与“等效”线性刷的简要比较。此外，我们的结果可以作为改进环状聚电解质刷作为独特表面改性剂的性能的指南。图形概要 。