Modeling competitive substitution in a polyelectrolyte complex
Modeling competitive substitution in a polyelectrolyte complex
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DOI：
10.1063/1.4936256
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发表时间：
2015-12-28
影响因子：
4.4
通讯作者：
Muthukumar, M.
中科院分区：
文献类型：
--
作者：
Peng, B.;Muthukumar, M.
我们用粗粒联合原子模型和朗之万动力学方法模拟了聚阳离子链和聚阴离子链组成的聚电解质络合物被另一个较长的聚阴离子链入侵的过程。我们的模拟揭示了取代反应的许多复杂细节，表现在链的构象变化以及入侵链与被置换为公共补链的链之间的竞争。我们证明了为了实现置换，入侵链需要比被取代的链足够长。然而，让入侵链比某个阈值更长并不会进一步减少替换时间。虽然大多数模拟都是在无盐条件下进行的，但我们发现盐的存在促进了取代反应，缩短了取代时间。对数据的分析表明，涉及聚电解质的取代过程的主要驱动力在于取代过程中反离子的释放。(C)2015 AIP出版有限责任公司。
We have simulated the invasion of a polyelectrolyte complex made of a polycation chain and a polyanion chain, by another longer polyanion chain, using the coarse-grained united atom model for the chains and the Langevin dynamics methodology. Our simulations reveal many intricate details of the substitution reaction in terms of conformational changes of the chains and competition between the invading chain and the chain being displaced for the common complementary chain. We show that the invading chain is required to be sufficiently longer than the chain being displaced for effecting the substitution. Yet, having the invading chain to be longer than a certain threshold value does not reduce the substitution time much further. While most of the simulations were carried out in salt-free conditions, we show that presence of salt facilitates the substitution reaction and reduces the substitution time. Analysis of our data shows that the dominant driving force for the substitution process involving polyelectrolytes lies in the release of counterions during the substitution. (C) 2015 AIP Publishing LLC.