The linear viscoelasticity of coacervates formed by oppositely charged polyelectrolytes in the salt solution is reviewed, with a focus on time-temperature, time-salt, time-pH, and time-hydration superpositions, and on fundamental relaxation mechanisms. A variety of polyelectrolyte pairs are covered, showing the frequent, but not universal, success of the time-salt superposition. Master curves in many cases are similar to those for neutral polymers, including Rouse and reptation theories. However, in some cases, solidlike, as opposed to fluidlike, response is observed at low frequencies, especially at low salt concentrations. Some coacervates seem to fit “sticky diffusion” theory reasonably well, wherein relaxation is controlled by the breakage rate of ion pairs; the dependence of the “sticker” lifetime on salt concentration has been explored but is not well understood as yet. It is also possible that local relaxation is not controlled by breakage of ion pairs but by cooperative, “glassy,” relaxation of monomers, salt ions, and water molecules. Compilation and comparison of different datasets and suggested formulas for rheological time constants are presented, and some suggestions are given for future directions.

中文翻译：

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聚电解质凝聚层中的线性粘弹性和时间-温度-盐等叠加

综述了盐溶液中带相反电荷的聚电解质形成的凝聚层的线性粘弹性，重点是时间-温度，时间-盐度，时间-pH和时间水合叠加，以及基本松弛机理。涵盖了各种聚电解质对，显示了时盐叠加的频繁但非普遍的成功。在许多情况下，主曲线与中性聚合物的主曲线相似，包括Rouse和Reptation理论。然而，在某些情况下，在低频率下，尤其是在低盐浓度下，观察到了固体状而不是液体状。一些凝聚层似乎非常适合“粘性扩散”理论，其中弛豫由离子对的断裂率控制；已经研究了“贴纸”寿命对盐浓度的依赖性，但目前尚不十分清楚。也可能不是通过离子对的破坏来控制局部弛豫，而是通过单体的协同“玻璃状”弛豫来控制，盐离子和水分子。介绍了流变时间常数的不同数据集的汇编和比较以及建议的公式，并对未来的发展方向提出了一些建议。