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采用分子动力学方法,对接枝在两相对平板上的有限尺寸聚电解质刷在良溶剂中的行为进行了研究。溶剂被视为隐性处理。通过改变板间距,考察了两刷的形态变化和相互作用机制。通过模拟发现,静电相互作用和体积排斥作用之间的相互竞争决定了聚电解质刷的动态行为。多价抗衡离子与接枝在不同板上的聚电解质链之间的桥接作用对刷高和压强有着重要影响。此外,相对于无限大的平板刷,有限尺寸聚电解质刷的自由度更大,导致其末端单体密度分布、刷高、桥接系数和压强随板间距的变化与无限尺寸体系不同。有限尺寸聚电解质平板刷体系与实验中的真实体系更相似,所得结论将对以后的实验研究具有一定的指导意义。
The molecular dynamics method was used to study the behavior of finite size polyelectrolyte brushes grafted on two opposite plates in a good solvent. Solvents are considered recessive. By changing the distance between the plates, the morphological changes and interaction mechanisms of the two brushes were investigated. The simulation shows that the interaction between electrostatic interaction and volume repulsion determines the dynamic behavior of polyelectrolyte brushes. The bridging effect between multivalent counterions and polyelectrolyte chains grafted onto different plates has an important effect on brush height and pressure. In addition, the limited size polyelectrolyte brushes are more flexible than infinite flatbed brushes, resulting in a variation in end-unit density distribution, brush height, bridging coefficient, and pressure with plate spacing that is different from an infinite size system. The finite size polyelectrolyte flat brush system is more similar to the real one in the experiment. The conclusion will be of guiding significance to the future experimental research.