Structure of Liquid Coacervates Formed by Oppositely Charged Polyelectrolytes
Structure of Liquid Coacervates Formed by Oppositely Charged Polyelectrolytes
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带相反电荷的聚电解质形成的液体凝聚层的结构
DOI：
10.1021/acs.macromol.8b02059
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发表时间：
2018
期刊：
影响因子：
5.5
通讯作者：
Sergey Panyukov
中科院分区：
文献类型：
--
作者：
Michael Rubinstein;Qi Liao;Sergey Panyukov
本文发展了一种标度理论，并对弱相互作用凝聚层进行了分子动力学模拟，其中每个电荷的静电相互作用能thermal.energykT。这种由带相反电荷的聚电解质形成的液体凝聚层在电荷密度和每条链的电荷数上可以是不对称的。我们预测，这些凝聚体形成互穿的解决方案，具有两个相关长度和两个.定性不同类型的构象的聚电解质.具有较低和较高的电荷密度，这是类似于.链构象在准中性和polyelectrolyte.solutions，分别。较弱的电荷链被吸引并吸附在较强的电荷链上，形成屏蔽。“外套”周围的较强的带电聚电解质。以较低浓度加入的盐屏蔽较强带电链之间的排斥，从而降低屏蔽涂层的厚度并导致凝聚层中的非零净聚合物电荷。在较高的盐浓度下，盐屏蔽了带相反电荷的链之间的吸引力，降低了凝聚层浓度及其聚合物电荷密度。因此，我们预测非对称凝聚层的聚合物电荷密度的非单调盐浓度依赖性。本文提出了不同组成的带相反电荷的聚电解质混合物在不同盐浓度下的相图。
We develop a scaling theory and perform.molecular dynamic simulations of weakly interacting coacervates.with electrostatic interaction energy per charge less than thermal.energy kT. Such liquid coacervates formed by oppositely charged.polyelectrolytes can be asymmetric in charge density and number.of charges per chain. We predict that these coacervates form.interpenetrating solutions with two correlation lengths and two.qualitatively different types of conformations of polyelectrolytes.with lower and higher charge densities, which are analogous to.chain conformations in quasi-neutral and in polyelectrolyte.solutions, respectively. Weaker charged chains are attracted to.and adsorbed on stronger charged chains forming a screening.“coat” around the stronger charged polyelectrolytes. Salt added at lower concentrations screens the repulsion between stronger.charged chains, thereby reducing the thickness of the screening coat and resulting in the nonzero net polymer charge in the.coacervate. At higher salt concentrations salt screens the attraction between oppositely charged chains, decreasing the.coacervate concentration and its polymeric charge density. Thus, we predict a nonmonotonic salt concentration dependence of.polymeric charge density for asymmetric coacervates. A phase diagram for a mixture of oppositely charged polyelectrolytes at.various compositions is proposed for different salt concentrations.