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.

中文翻译：

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具有适应性构象的聚电解质的可逆离子结合

根据链内排斥的强度和有效电荷密度，聚电解质可以采用棒状或线圈状构象。聚电解质的电荷密度不仅受小离子结合的影响，还受与带相反电荷链的结合的影响。我们引入了一种耦合变分方法，可以同时处理可逆离子结合、自适应链结构和静电相关性。这种方法捕获了单个聚电解质链的溶胀和消胀，以及聚电解质混合物中链间交联和离子结合之间的竞争。应用我们的理论来研究聚电解质凝聚，我们确定了两种不同的制度。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。在强结合状态下，这种依赖性减弱，溶液热力学受短程离子结合平衡支配。