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摘要翻译：
采用Langevin动力学模拟，在粗粒模型框架下研究了单一聚电解质在四价盐溶液中的构象。通过回转半径的方法研究了链的尺寸随盐浓度的变化规律，并根据链的刚度的不同表现出三种不同的变化规律。根据这些行为，将固定链长的聚电解质分为三类：柔性链、半柔性链和刚性链。由Odijk-Skolnick-Fixman理论预测的具有持续长度的蠕虫链模型可以定性地描述低盐浓度下的端到端距离。在低盐区，柔性聚电解质比半柔性链延伸得更明显，而在高盐区，无论链的刚度如何，链的尺寸都达到与其中性聚合物相当的尺寸。链的刚度对链的局部结构和整体结构都有影响。在盐离子存在下，柔性链呈现出锯齿状的局域结构，凝聚结构是无序的、无规的球状结构。半柔性链局部光滑，凝聚结构有序堆积，呈发夹或环形等形式。此外，链刚度也会影响线圈-球状转变的性质。对于半柔性链，这种转变是以离散的方式发生的，而对于柔性链，这种转变是以连续的方式发生的。这种离散性不仅在低盐浓度下半柔性链发生坍缩，而且在高盐浓度下半柔性链发生再膨胀时也出现了这种离散性。最后以状态示意图的形式总结了链刚度和盐浓度对单聚电解质构象的影响。
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英文标题：
《Role of chain stiffness on the conformation of single polyelectrolytes
in salt solutions》
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作者：
Yu-Fu Wei and Pai-Yi Hsiao
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最新提交年份：
2007
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分类信息：
一级分类：Physics 物理学
二级分类：Soft Condensed Matter 软凝聚态物质
分类描述：Membranes, polymers, liquid crystals, glasses, colloids, granular matter
膜，聚合物，液晶，玻璃，胶体，颗粒物质
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一级分类：Physics 物理学
二级分类：Statistical Mechanics 统计力学
分类描述：Phase transitions, thermodynamics, field theory, non-equilibrium phenomena, renormalization group and scaling, integrable models, turbulence
相变，热力学，场论，非平衡现象，重整化群和标度，可积模型，湍流
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英文摘要：
Conformation of single polyelectrolytes in tetravalent salt solutions is investigated under the framework of a coarse-grained model, using Langevin dynamics simulations. The chain size, studied by the radius of gyration, shows three different variational behaviors with salt concentration, depending on the chain stiffness. According to these behaviors, polyelectrolytes of fixed chain length are classified into three categories: flexible chain, semiflexible chain, and rigid chain. The worm-like chain model with persistence length predicted by the Odijk-Skolnick-Fixman theory is found to be able to qualitatively describe the end-to-end distance at low salt concentration. In a low-salt region, a flexible polyelectrolyte extends more significantly than a semiflexible chain, and in a high-salt region, regardless of chain stiffness, a chain attains a dimension comparable to that of its neutral polymer. The chain stiffness influences both the local and the global chain structures. A flexible chain exhibits a zigzagged local structure in the presence of salt ions and the condensed structure is a disordered, random globule. A semiflexible chain is locally smooth, and the condensed structure is orderly packed, taking a form such as hairpin or toroid. Moreover, the chain stiffness can also affect the nature of the coil-globule transition. The transition is occurred in a discrete manner for semiflexible chain, whereas in a continuous way for flexible chain. This discrete feature is happened not only at low salt concentration when a semiflexible chain is collapsed, but also at high salt concentration when the collapsed chain is reexpanded. At the end, the effects of chain stiffness and salt concentration on the conformation of single polyelectrolytes are summarized in a schematic state diagram.
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PDF链接：
https://arxiv.org/pdf/705.4605
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