The Thiouronium Group for Ultrastrong Pairing Interactions between Polyelectrolytes
The Thiouronium Group for Ultrastrong Pairing Interactions between Polyelectrolytes
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聚电解质之间超强配对相互作用的硫脲基团
DOI：
10.1021/acs.jpcb.0c07456
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Schlenoff, Joseph B.
中科院分区：
文献类型：
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作者：
Lteif, Sandrine;Abou Shaheen, Samir;Schlenoff, Joseph B.
各种带电基团可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。由此形成的材料被称为凝聚复合物或凝聚物（佩奇）。正性Pol+和负性Pol-重复单元之间的配对强度取决于单体重复单元的特定身份。在这项工作中，硫脲基团，一个阳离子密切相关的胍，配对强度进行了评估，使用聚硫脲。含有胍盐的聚合物，特别是聚精氨酸（一种肽），因其不寻常的行为而闻名，如形成电荷相同的离子对和氢键。它在这里示出，这种行为的一部分是结转到聚硫脲，这导致在异常强烈的相互作用与聚阴离子，如聚磺酸盐和聚羧酸盐。使用在各种盐浓度下的聚硫脲多层膜的累积和通过用高浓度的添加盐破坏预先形成的佩奇来评价聚硫脲/Pol相互作用的弹性。硫脲基团甚至与聚合物两性离子足够强烈地相互作用，以使得能够与这种名义上弱相互作用的净中性聚合物络合。
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.