Emergence of Multiscale Dynamics in Colloidal Gels

Abstract

To gain insight into the kinetics of colloidal gel evolution at low particle volume fractions $\varphi$, we utilize differential dynamic microscopy to investigate particle aggregation, geometric percolation, and the subsequent transition to nonergodic dynamics. We report the emergence of unexpectedly rich multiscale dynamics upon the onset of nonergodicity, which separates the wave vectors $q$ into three different regimes. In the high-$q$ domain, the gel exhibits $\varphi$-independent internal vibrations of fractal clusters. The intermediate-$q$ domain is dominated by density fluctuations at the length scale of the clusters, as evidenced by the $q$-independence of the relaxation time $\tau$. In the low-$q$ domain, the scaling of $\tau$ as $q^{-3}$ suggests that the network appears homogeneous. The transitions between these three regimes introduce two characteristic length scales, distinct from the cluster size.

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• Yield precursor in primary creep of colloidal gels
• Two-color differential dynamic microscopy for capturing fast dynamics
• Structural and dynamical properties of gel networks
• Universal Critical Behavior of Percolation in Orientationally Ordered Janus Particles and Other Anisotropic Systems
• Correlated rigidity percolation in fractal lattices
• The Hitchhiker's Guide to Differential Dynamic Microscopy
• A simple method to reprogram the binding specificity of DNA-coated colloids that crystallize
• Convolutional neural networks applied to differential dynamic microscopy reduces noise when quantifying heterogeneous dynamics
• Pole Analysis of the Inter-Replica Correlation Function in a Two-Replica System as a Binary Mixture: Mean Overlap in the Cluster Glass Phase
• Two Modes of Cluster Dynamics Govern the Viscoelasticity of Colloidal Gels