Conformational study on sol-gel transition in telechelic polyelectrolytes solutions.
Conformational study on sol-gel transition in telechelic polyelectrolytes solutions.
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DOI：
10.1021/jp9092404
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发表时间：
2010-02
期刊：
影响因子：
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通讯作者：
Ran Zhang;T. Shi;L. An;Zhao‐Yan Sun;Z. Tong
中科院分区：
文献类型：
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作者：
Ran Zhang;T. Shi;L. An;Zhao‐Yan Sun;Z. Tong
采用蒙特卡罗模拟方法研究了一种由柔性线性聚电解质和两端短疏水块组成的特殊缔合聚电解质——远螺旋聚电解质。研究发现，疏水引力与远距离静电相互作用之间的相互作用以及反离子分布对链构象（环和非环两种基本构象）、缔合行为（环缔合有助于环构象；自由链、悬垂链和桥链有助于非环构象）和簇的形成有重要影响。当浓度接近重叠浓度phi*时，发现在强疏水相互作用下，簇进一步通过桥链连接，形成三维网络。此外，增加库仑相互作用强度有利于凝胶网络的形成。随着库仑相互作用强度的增加，由于来自反离子冷凝层的屏蔽，第一链呈现先延伸后坍塌的趋势。
A special kind of associating polyelectrolytes, telechelic polyelectrolytes, composed of a flexible linear polyelectrolyte and short hydrophobic blocks at both ends, is investigated by means of Monte Carlo simulations in aqueous media. It is found that the interplay between hydrophobic attraction and the long-range electrostatic interaction as well as the counterion distribution exerts a major influence on the chain conformations (two basic conformations: loop and nonloop), association behavior (loop association contributes to loop conformation; free, dangling, and bridge chains contribute to nonloop conformations), and the forming of clusters. At a concentration close to the overlapping concentration phi*, the clusters are found to be further connected by bridge chains under strong hydrophobic interaction, forming a 3D network. In addition, increasing Coulombic interaction strength is in favor of the formation of a gel network. With increasing Coulombic interaction strength, first chains tend to extend and then tend to collapse due to the screening originating from the counterion condensation layer.