Self-Diffusion in a Weakly Entangled Associative Network
Self-Diffusion in a Weakly Entangled Associative Network
复制标题
弱纠缠关联网络中的自扩散
DOI：
10.1021/acs.macromol.2c00295
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发表时间：
2022
期刊：
影响因子：
5.5
通讯作者：
Olsen, Bradley D.
中科院分区：
文献类型：
--
作者：
Mahmad Rasid, Irina;Rao, Ameya;Holten-Andersen, Niels;Olsen, Bradley D.
缔合聚合物凝胶中缠结的存在被证明能够增强机械强度、韧性和延展性；然而，这些体系中的拓扑和结合作用之间的相互作用仍然知之甚少。在弱纠缠区，对应于1.13.1ϕe，研究了模型缔合网络中纠缠对链动力学的影响，其中ϕe是开始纠缠的特征浓度。缔合网络是由N，N-二甲基丙烯酰胺的线性无规共聚物和组氨酸功能化的单体与Ni2+离子交联形成的。流变学表征表明，所研究的浓度跨越了从无纠缠区到弱纠缠区的转变，导致其弛豫谱略有加宽。用强迫瑞利散射测量的自扩散表明，随着浓度的增加，表观超扩散行为受到明显的抑制，这表明与整体网络弛豫相比，拓扑纠缠对自扩散的影响更大。这种对超扩散行为的抑制归因于由于纠缠的存在而减少了“跳跃”扩散的贡献，导致了在所探测的最高浓度下由单一的“行走”扩散模式控制的纯费克扩散的方法。这些结果证明了纠缠对缔合网络中自扩散和驰豫的显著影响，提供了对网络响应的洞察，而不仅仅是流变学所能达到的。
The presence of entanglements in associative polymer gels has been shown to impart enhanced mechanical strength, toughness, and extensibility; however, the interplay between topological and binding interactions in these systems remains poorly understood. Here, the effect of entanglements on chain dynamics in a model associative network is investigated in the weakly entangled regime, corresponding to 1.1–3.1ϕe, where ϕeis the characteristic concentration for the onset of entanglement. The associative network is formed by a linear random copolymer ofN,N-dimethylacrylamide and a histidine-functionalized monomer crosslinked with Ni2+ions. Rheological characterization indicates that the concentrations investigated span the transition from unentangled to the weakly entangled regime, resulting in a subtle broadening of their relaxation spectrum. Self-diffusion measurements using forced Rayleigh scattering demonstrate a pronounced suppression of apparent superdiffusive behavior with increasing concentration, revealing a stronger impact of topological entanglement on self-diffusion compared to overall network relaxation. This suppression in superdiffusive behavior is attributed to a reduction in the contribution of “hopping” diffusion due to the presence of entanglements, resulting in an approach to purely Fickian diffusion governed by a single “walking” diffusive mode at the highest concentration probed. These results demonstrate the marked effects of entanglements on self-diffusion and relaxation in associative networks, providing insight into the network response beyond that accessible by rheology alone.
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影响因子：
5.5
作者：
Tang, Shengchang;Glassman, Matthew J.;Li, Shuaili;Socrate, Simona;Olsen, Bradley D.
通讯作者：
Olsen, Bradley D.
影响因子：
5.5
作者：
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通讯作者：
Gabriel E. Sanoja;Nicole S. Schauser;J. Bartels;C. M. Evans;M. Helgeson;R. Seshadri;R. Segalman
影响因子：
5.5
作者：
Stukalin, Evgeny B.;Cai, Li-Heng;Kumar, N. Arun;Leibler, Ludwik;Rubinstein, Michael
通讯作者：
Rubinstein, Michael
关于弱缠结和强缠结线性聚合物之间的区别
影响因子：
3.1
作者：
Yu. A. Altukhov;V. Pokrovskii;G. Pyshnograi
通讯作者：
G. Pyshnograi
影响因子：
3.4
作者：
Glassman MJ;Olsen BD
通讯作者：
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