Cation-Specific Conformational Behavior of Polyelectrolyte Brushes: From Aqueous to Nonaqueous Solvent
Cation-Specific Conformational Behavior of Polyelectrolyte Brushes: From Aqueous to Nonaqueous Solvent
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聚电解质刷的阳离子特异性构象行为：从水溶剂到非水溶剂
DOI：
10.1021/la5033493
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发表时间：
2014
期刊：
影响因子：
3.9
通讯作者：
Liu Guangming
中科院分区：
文献类型：
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作者：
Wang Tao;Long Yunchao;Liu Lvdan;Wang Xiaowen;Craig Vincent S. J.;Zhang Guangzhao;Liu Guangming
我们使用耗散石英晶体微量天平（QCM-D）研究了当溶剂从水变为甲醇时聚苯乙烯磺酸钠（PSS）刷的阳离子特异性构象行为的变化。的溶剂化去溶剂化过渡的接枝链伴随着溶胀的崩溃过渡的刷观察Na+。在Cs+的情况下，刷子经历溶剂化去溶剂化再溶解，伴随着溶胀塌陷再溶胀的转变。Cs+的溶解和再溶胀转变是通过Cs+与刷之间的货车德瓦耳斯相互作用引起的刷的电荷反转引起的。随着甲醇含量的增加，一价阳离子的所有转变变得不那么明显。对于二价的Ca ~（2+）和三价的La ~（3+），可以观察到接枝链从溶剂化到去溶剂化再到溶剂化的转变，并伴随着刷子从溶胀到塌陷再溶胀的转变。多价阳离子刷的溶解和再溶胀是由刷的电荷反转通过电荷图像电荷相互作用引起的。的PSS刷在多价阳离子的存在下的过渡的程度仅受甲醇含量的轻微影响。
We have investigated changes in the cation-specific conformational behavior of poly(sodium styrenesulfonate) (PSS) brushes as the solvent changes from water to methanol using a quartz crystal microbalance with dissipation (QCM-D). A solvation to desolvation transition of the grafted chains accompanied by swelling to the collapse transition of the brushes is observed for Na+. In the case of Cs+, the brushes undergo solvation to desolvation to resolvation accompanied by swelling to collapse to reswelling transitions. The resolvation and reswelling transitions for Cs+are induced by the charge inversion of the brushes via van der Waals interactions between Cs+and the brushes. All of the transitions for monovalent cations become less obvious as the methanol content increases. For divalent Ca2+and trivalent La3+, a solvation to desolvation to resolvation transition of the grafted chains accompanied by a swelling to collapse to reswelling transition of the brushes can be observed. The resolvation and reswelling of the brushes for the multivalent cations are induced by the charge inversion of the brushes via charge-image charge interactions. The extent of the transitions for the PSS brushes in the presence of multivalent cations is only slightly influenced by the methanol content.