Viscoelasticity in associating oligomers and polymers: experimental test of the bond lifetime renormalization model
Viscoelasticity in associating oligomers and polymers: experimental test of the bond lifetime renormalization model
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DOI：
10.1039/c9sm01930h
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发表时间：
2020-01-14
期刊：
影响因子：
3.4
通讯作者：
Sokolov, Alexei P.
中科院分区：
文献类型：
--
作者：
Ge, Sirui;Tress, Martin;Sokolov, Alexei P.
最近的发现，缔合聚合物的缔合键寿命tau(α*)偏离了它们的超分子网络弛豫时间tau(C)，这对过去的理论提出了挑战。Rubinstein和他的同事提出的键寿命重整化[Stukalin等人，大分子，2013，46,7525]提供了一个有希望的解释。为了系统地考察它的适用性，我们用剪切流变学和介电光谱研究了不同主链(聚丙二醇和聚二甲基硅氧烷)、不同相对分子质量(低于缠结相对分子质量)和端基(酰胺和羧酸)通过氢键形成二聚体缔合的遥控缔合聚合物。根据模型的定性预测，tau(C)(流变学探测)和tau(α*)(介电光谱探测)之间的分离随着链长的增加而显著增加。然而，为了定量地描述增长，必须假设从上升到上升动力学的转变。这表明，必须考虑超链的动力学才能正确地描述暂态网络。
Recent findings that the association bond lifetimes tau(alpha*) in associating polymers diverge from their supramolecular network relaxation times tau(c) challenge past theories. The bond lifetime renormalization proposed by Rubinstein and coworkers [Stukalin et al., Macromolecules, 2013, 46, 7525] provides a promising explanation. To examine systematically its applicability, we employ shear rheology and dielectric spectroscopy to study telechelic associating polymers with different main chain (polypropylene glycol and polydimethylsiloxane), molecular weight (below entanglement molecular weight) and end groups (amide, and carboxylic acid) which form dimeric associations by hydrogen bonding. The separation between tau(c) (probed by rheology) and tau(alpha*) (probed by dielectric spectroscopy) strongly increases with chain length as qualitatively predicted by the model. However, to describe the increase quantitatively, a transition from Rouse to reptation dynamics must be assumed. This suggests that dynamics of super-chains must be considered to properly describe the transient network.