Advances in synthetic chemistry have led to greater control over the sequence of polymeric materials, and the ability to create patterns whose complexity is reminiscent of that of biological macromolecules. In random copolymers synthesized via statistical copolymerization, the sequence follows a first-order Markov chain process governed by the underlying reactivity ratios. In this work, theory and simulations are combined to study the role of sequence in the complex coacervation of oppositely charged random (co)polyelectrolytes, i.e. copolymers comprising cationic/anionic and neutral monomers. It is found that charged monomers enhance the proclivity towards complex coacervation, and enhance the coacervates' stability upon addition of salt. This result is general, and holds for both good and poor solvents, despite the different (“closed” and “open”) shapes of the respective coacervation binodals. For high charge blockiness, simulations reveal the formation of microphase separated coacervates consisting of domains rich in ionic or neutral monomers. The transition from homogeneous to locally segregated coacervates leads to a non-monotonic dependence of the density on charge blockiness. Our results provide a comprehensive framework to understand and interpret the effects of sequence on complex coacervation, and for rational design of coacervate-based materials.

中文翻译：

---

统计聚电解质的复杂凝聚：单体序列的作用和不均匀凝聚层的形成

合成化学的进步使人们能够更好地控制聚合物材料的序列，并能够创造出复杂性类似于生物大分子的模式。在通过统计共聚合成的无规共聚物中，序列遵循由潜在反应率控制的一阶马尔可夫链过程。在这项工作中，理论和模拟相结合来研究序列在带相反电荷的随机（共）聚电解质的复杂凝聚中的作用，即包含阳离子/阴离子和中性单体的共聚物。发现带电单体增强了复合凝聚的倾向，并在加入盐时增强凝聚层的稳定性。尽管各个凝聚双节点的形状不同（“封闭”和“开放”），但该结果是一般性的，并且适用于良溶剂和不良溶剂。对于高电荷阻断性，模拟揭示了微相分离凝聚层的形成，该凝聚层由富含离子或中性单体的域组成。从均匀到局部分离的凝聚层的转变导致密度对电荷块度的非单调依赖性。我们的结果为理解和解释序列对复杂凝聚的影响以及基于凝聚层的材料的合理设计提供了一个全面的框架。