We utilize dynamic light scattering (DLS)-based passive microrheology to probe the dynamics and structural evolution of laponite® and laponite®-polymer glasses and dispersions at the microscale. The results reveal an increase in the dynamic heterogeneity of laponite® dispersions with an increase of laponite® concentration and aging time. In neat laponite® dispersions, the degree of stiffness is enhanced and the dynamics are retarded at higher laponite® concentration due to the formation of a repulsive glass. In the presence of PEO with a moderate molecular weight of 20 kg/mol, the microviscoelastic properties of 2 wt% laponite® dispersions show non-monotonic effects with PEO concentration upon aging, which agrees with the results obtained previously from bulk rheology. However, the magnitudes of the viscoelastic moduli ( G’ and G” ) of dispersions beyond the gel point obtained from DLS-microrheology is lower than that obtained from conventional rheology. Our results suggest that the DLS-microrheology can be used to qualitatively study dynamic transitions and the microviscoelastic properties of gels and soft solids. Graphical abstract

中文翻译：

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laponite® 和 laponite®-聚（环氧乙烷）玻璃和分散体的微观结构、微流变学和动力学

我们利用基于动态光散射 (DLS) 的被动微流变学在微观尺度上探测 laponite® 和 laponite®-聚合物玻璃和分散体的动力学和结构演变。结果表明，随着 laponite® 浓度和老化时间的增加，laponite® 分散体的动态非均质性增加。在纯 laponite® 分散体中，由于形成了排斥性玻璃，因此在较高的 laponite® 浓度下，刚度会增强，而动力学会延迟。在中等分子量为 20 kg/mol 的 PEO 的存在下，2 wt% laponite® 分散体的微粘弹性性能随着 PEO 浓度的老化显示出非单调效应，这与之前从体积流变学中获得的结果一致。然而，从 DLS 微流变学获得的超过胶凝点的分散体的粘弹性模量（G' 和 G”）的大小低于从传统流变学获得的值。我们的结果表明，DLS 微流变学可用于定性研究凝胶和软固体的动态转变和微粘弹性。图形概要