Relaxation and Dynamics in Transient Polymer Model Networks
Relaxation and Dynamics in Transient Polymer Model Networks
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DOI：
10.1021/ma5013144
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发表时间：
2014-09-23
期刊：
影响因子：
5.5
通讯作者：
Seiffert, Sebastian
中科院分区：
文献类型：
--
作者：
Rossow, Torsten;Habicht, Axel;Seiffert, Sebastian
超分子聚合物网络作为自修复软材料具有广阔的应用前景。为了从这种能力中受益，必须实现对大分子动力学和瞬时缔合的潜在机制的定量理解。获得这种理解的关键是理解超分子聚合物网络的动力学和松弛，这通常是复杂的不均匀的聚合物网络结构。为了克服这一限制，我们使用一组规则的星形聚（乙二醇）聚合物封端与三联吡啶基团，可以瞬时协调不同的金属离子，从而形成瞬时的超分子聚合物网络与确定的均匀架构和确定的结合强度。我们研究这些网络的力学，动力学，并从宏观和微观的角度，通过使用流变学，动态光散射，和荧光恢复后光漂白。这些研究表明，虽然在长期的平均网络表现出的连接性增强，时间分离的星形聚合物积木的一个臂允许他们在网络内的重新定位，需要在长时间尺度上的松弛和流动。
Supramolecular polymer networks have promising potential to serve as self-healing soft materials. To benefit from this ability, quantitative understanding of the underlying mechanisms of macromolecular dynamics and transient association must be achieved. A key to obtaining such understanding is to understand the dynamics and relaxation of supramolecular polymer networks, which is often complexed by inhomogeneous polymer-network structures. To overcome this limitation, we use a set of regular star-shaped poly(ethylene glycol) polymers end-capped with terpyridine groups that can transiently coordinate to different metal ions, thereby forming transient supramolecular polymer networks with determined homogeneous architectures and determined binding strength. We study these networks in view of their mechanics, dynamics, and from both macroscopic and microscopic perspectives through the use of rheology, dynamic light scattering, and fluorescence recovery after photobleaching. These studies reveal that whereas in a long-term average the networks exhibit percolated connectivity, temporal detachment of one of the arms of the star-polymer building blocks allows for their relocation within the networks, entailing relaxation and flow on long time scales.