Reversible ion binding for polyelectrolytes with adaptive conformations
Reversible ion binding for polyelectrolytes with adaptive conformations
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DOI：
10.1002/aic.17426
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发表时间：
2021-09-13
期刊：
影响因子：
3.7
通讯作者：
Qin, Jian
中科院分区：
文献类型：
--
作者：
Friedowitz, Sean;Qin, Jian
聚电解质可以采用棒状或螺旋状构象，这取决于链内排斥的强度和有效电荷密度。聚电解质的电荷密度不仅受小离子结合的影响，而且受与带相反电荷的链的结合的影响。我们介绍了一个耦合变分方法，同时对待可逆的离子结合，自适应链结构和静电相关。这种方法捕获的溶胀和去溶胀的单链，和链间交联和离子结合的聚电解质的混合物之间的竞争。应用我们的理论来研究复凝聚，我们确定了两个不同的制度。在弱结合状态下，电荷密度高，溶液性质取决于聚电解质的构象。在强结合区，这种依赖性减弱，溶液热力学主要由短程离子结合平衡决定。
Polyelectrolytes may adopt rod- or coil-like conformations depending on the strength of intrachain repulsion and the effective charge density. The charge density of polyelectrolytes is influenced not only by the binding of small ions, but also by the binding with oppositely charged chains. We introduce a coupled variational approach that treats reversible ion binding, adaptive chain structure, and electrostatic correlations simultaneously. This approach captures the swelling and deswelling of single polyelectrolyte chains, and the competition between interchain cross-linking and ion binding in mixtures of polyelectrolytes. Applying our theory to study polyelectrolyte coacervation, we identify two distinct regimes. In the weak binding regime, the charge density is high and the solution properties are dependent on the conformations of polyelectrolytes. In the strong binding regime, this dependence is weakened and the solution thermodynamics are dominated by the short-range ion-binding equilibrium.