Theory of counter-ion condensation on flexible polyelectrolytes: Adsorption mechanism
Theory of counter-ion condensation on flexible polyelectrolytes: Adsorption mechanism
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DOI：
10.1063/1.1701839
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发表时间：
2004-05-15
影响因子：
4.4
通讯作者：
Muthukumar, M
中科院分区：
文献类型：
--
作者：
Muthukumar, M
本文提出了一个新的计算柔性聚电解质表面反离子分布的模型，该模型考虑了（i）反离子链的自由能，（ii）吸附反离子的平动熵，（iii）吸附能，（iv）未吸附反离子的平动熵，（v）离解离子的涨落，（vi）吸附反离子形成的离子对之间的关联。自洽地计算聚合物的有效电荷和尺寸。聚合物的电离度f随1/ε T（ε T和T分别是溶剂和温度的介电常数）连续减小，这敏感地取决于局部介电异质性。此外，f随着盐浓度、单体浓度或链柔性的增加而降低。随着f的变化，聚合物的尺寸非单调地依赖于1/ε T。该模型的预测与以前在模拟中观察到的所有趋势是一致的，是明显不同的曼宁参数棒状链。(C)2004年，美国物理学会。
A new model is presented for counterion distribution around flexible polyelectrolytes by considering (i) free energy of the polyelectrolyte chain, (ii) translational entropy of adsorbed counterions, (iii) adsorption energy, (iv) translational entropy of unadsorbed counterions, (v) fluctuations of dissociated ions, and (vi) correlation among ion-pairs formed by adsorbed counterions on the polymer. The effective charge and size of the polymer are calculated self-consistently. The degree of ionization f of the polymer decreases continuously with 1/epsilonT (epsilon and T are the dielectric constant of the solvent and temperature, respectively), depending sensitively on local dielectric heterogeneity. Further, f decreases with an increase in salt concentration, monomer concentration, or chain flexibility. The polymer size, accompanying the changes in f, depends nonmonotonically on 1/epsilonT. The predictions of the model are consistent with all trends observed previously in simulations and are distinctly different from the Manning argument for rodlike chains. (C) 2004 American Institute of Physics.