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外文期刊>The Journal of Chemical Physics
>Mean field theory for the intermoIecular and intramolecular conformational transitions of a single flexible polyelectrolyte chain
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Mean field theory for the intermoIecular and intramolecular conformational transitions of a single flexible polyelectrolyte chain
The diMarzio theory has been extended to elucidate the intermolecular and intramolecular phase segregations of a single flexible chain polyelectrolyte in dilute salt-free solutions.At the long chain limit,this theory yields the formalism obtained from the more sophisticated Edward Hamiltonian for polyelectrolyte problems.The calculated phase diagram exhibits the features of a first-order phase transition,with continuous and discontinuous transitions separated by a critical point.Under the discontinuous transition,the polyelectrolyte chain exhibits coexistent expanded and collapsed conformational states,same as intermolecular phase segregation.For a limiting long chain,the mean chain size at critical point is roughly 90% of the size of an ideal chain.Such a result implies that partial contraction within a chain molecule is required to collapse a flexible polyelectrolyte chain.Moreover,the theory predicts that for a longer chain,intramolecular segregated conformations differ significantly from intermolecular segregated conformations,but the difference becomes small for shorter chains.Besides,the charge needed to induce intramolecular segregation is smaller than that of intermolecular segregation for a given chain length.These findings are consistent with previous literature results.
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机译：扩展了diMarzio理论以阐明在稀无盐溶液中单个柔性链状聚电解质的分子间和分子内相分离。在长链极限下，该理论产生了从更复杂的Edward Edward Hamilton获得的关于聚电解质问题的形式主义。计算出的相图表现出一阶相变的特征，连续和不连续的转变被临界点隔开。在不连续的转变下，聚电解质链表现出共存的扩张和塌缩构象状态，与分子间的相分离相同。长链，临界点的平均链长约为理想链大小的90％。结果表明，链分子内的部分收缩需要使柔性聚电解质链折叠。此外，该理论预测较长的链，分子内分离的构象差异显着y是由分子间分离的构象产生的，但对于较短的链而言，差异变得很小。此外，在给定的链长下，诱导分子内分离的电荷小于分子间分离的电荷。这些发现与先前的文献结果一致。
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