Various charged groups may be used as a repeat unit in polyelectrolytes to provide physical interactions between oppositely charged polymers leading to phase separation. The materials formed thus are termed polyelectrolyte complexes or coacervates (PECs). The strength of pairing between positive, Pol⁺, and negative, Pol^–, repeat units depends on the specific identity of the monomer repeat unit. In this work, the pairing strength of the thiouronium group, a cation closely related to guanidinium, is evaluated using a polythiouronium polyelectrolyte. Polymers containing guanidinium, notably polyarginine, a peptide, are known for their unusual behavior, such as the formation of like-charge ion pairs and hydrogen bonding. It is shown here that some of this behavior is carried over to polythiouroniums, which results in exceptionally strong interactions with polyanions such as polysulfonates and polycarboxylates. The resilience of the polythiouronium/Pol^– interaction was evaluated using the buildup of polyelectrolyte multilayers at various salt concentrations and by breaking up preformed PECs with high concentrations of added salt. The thiouronium group even interacts strongly enough with polymeric zwitterions to enable complexation with this nominally weakly interacting, net-neutral polymer.

中文翻译：

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聚电解质之间超强配对相互作用的硫脲基团

各种带电基团可以用作聚电解质中的重复单元，以提供带相反电荷的聚合物之间的物理相互作用，从而导致相分离。因此形成的材料称为聚电解质络合物或凝聚层（PEC）。正（Pol ⁺）和负（Pol ^–）之间的配对强度重复单元取决于单体重复单元的具体特性。在这项工作中，使用聚硫脲鎓聚电解质评估了与铀鎓紧密相关的阳离子硫脲鎓基团的配对强度。含有胍盐的聚合物，特别是聚精氨酸（一种肽），以其不寻常的行为而著称，例如形成相同电荷的离子对和氢键。在此表明，某些这种行为会延续到聚硫脲鎓上，这导致与聚阴离子（如聚磺酸盐和聚羧酸盐）的相互作用特别强。聚硫脲鎓/ Pol的弹性^–通过在各种盐浓度下聚电解质多层的堆积以及通过用高浓度的盐破坏预制的PEC来评估相互作用。硫脲鎓基团甚至可以与聚合两性离子发生足够强的相互作用，从而能够与这种名义上相互作用较弱的净中性聚合物络合。