Multiscale Dynamics of Inhomogeneity-Free Polymer Gels
Multiscale Dynamics of Inhomogeneity-Free Polymer Gels
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DOI：
10.1021/ma402439v
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发表时间：
2014-01-28
期刊：
影响因子：
5.5
通讯作者：
Shibayama, Mitsuhiro
中科院分区：
文献类型：
--
作者：
Hiroi, Takashi;Ohl, Michael;Shibayama, Mitsuhiro
为了准确地理解凝胶的动力学，有必要区分固有交联的影响和伴随的不均匀性。这种分离是通过使用无非均相的凝胶，如四聚乙二醇凝胶来实现的。我们用准弹性散射的方法研究了四聚乙二醇凝胶的动力学。通过动态光散射（DLS）测量介观（长度尺度：类似于100 nm）运动。除了这个尺度，我们还使用中子自旋回波（NSE）来测量微观（长度尺度：类似于1 nm）运动。从这些测量结果可以看出，无连通或拓扑不均匀性的凝胶在更大的长度尺度上表现出从齐姆模式向集体扩散模式的转变，甚至超出了NSE的q范围。除此之外，空间不均匀性的缺失还表现为中间动态结构因子中非衰变分量的消失。通过DLS和NSE的联合分析，阐明了凝胶的多尺度动力学。
For precise understanding of the dynamics of gels, it is necessary to distinguish the effect of inherent cross-linking from accompanying inhomogeneity. This separation is realized by the use of inhomogeneity-free gel such as Tetra-PEG gel. We investigated the dynamics of Tetra-PEG gel by quasi-elastic scattering. Mesoscopic (length scale: similar to 100 nm) motion was measured by dynamic light scattering (DLS). In addition to this scale, we used neutron spin echo (NSE) to measure microscopic (length scale: similar to 1 nm) motion. From these measurements, it is revealed that the gels with no connectivity/topological inhomogeneities show the transition from Zimm mode to collective diffusion mode in larger length scale, even beyond the q-range of NSE. In addition to this, the absence of spatial inhomogeneities is reflected as disappearance of nondecay component in the intermediate dynamic structure factor. Through the combination analysis of DLS and NSE, the multiscale dynamics of gels is elucidated.