Necklace globule and counterion condensation
Necklace globule and counterion condensation
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DOI：
10.1021/ma071005k
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发表时间：
2007-10-16
期刊：
影响因子：
5.5
通讯作者：
Dobrynin, Andrey V.
中科院分区：
文献类型：
--
作者：
Jeon, Junhwan;Dobrynin, Andrey V.
我们提出了一个项链模型，其中的项链结构是由于在主链上的反离子凝聚的结果。这种项链结构优化了凝聚的反离子和带电单体的相关诱导吸引力和未补偿电荷之间的静电排斥力。这种项链小球的新特征是它甚至可以在聚合物主链的良好溶剂条件下形成。通过标度分析，我们计算了聚合物主链的溶剂质量和Bjerrum长度的值作为函数的链的状态图。为了测试的缩放模型的预测，我们已经进行了分子动力学模拟的聚合度N = 124-304和分数的带电单体f= 1/3的聚合物主链在良好的，θ，和不良的溶剂条件下的聚合物链。我们已经确定的参数范围内的项链小球形成由于相关诱导的吸引力的相互作用，在良好的溶剂条件下的聚合物骨架。分子动力学模拟的结果与标度模型的预测定性一致。
We have developed a necklace model of polyelectrolyte chain in which the necklace structure appears as a result of the counterion condensation on the polyelectrolyte backbone. This necklace structure optimizes the correlation-induced attraction of the condensed counterions and charged monomers and electrostatic repulsion between uncompensated charges. The new feature of this necklace globule is that it can be formed even in good solvent conditions for the polymer backbone. By using the scaling analysis, we have calculated the diagram of state of polyelectrolyte chain as a function of the solvent quality for the polymer backbone and value of the Bjerrum length. To test the predictions of a scaling model, we have performed molecular dynamics simulations of polyelectrolyte chains with the degrees of polymerizations N = 124-304 and fraction of charged monomers f= 1/3 in good, theta, and poor solvent conditions for the polymer backbone. We have identified the range of parameters in which the necklace globule is formed due to correlation-induced attractive interactions in the good solvent conditions for the polymer backbone. The results of the molecular dynamics simulations are in qualitative agreement with the predictions of a scaling model.