Microscopic dynamics underlying the stress relaxation of arrested soft materials
Name
song-et-al-2022-microscopic-dynamics-underlying-the-stress-relaxation-of-arrested-soft-materials.pdf
Size
1.74 MB
Format
Adobe PDF
Checksum (MD5)
fa07a1f2080ae20864aa178259f94969
Author(s)
Song, Jake
Zhang, Qingteng
de Quesada, Felipe
Rizvi, Mehedi H.
Tracy, Joseph B.
Ilavsky, Jan
Narayanan, Suresh
Del Gado, Emanuela
Leheny, Robert L.
Holten-Andersen, Niels
Date Issued
July 19, 2022
Journal
Proceedings of the National Academy of Sciences
Publisher
Proceedings of the National Academy of Sciences
Citation
Song, Jake, Zhang, Qingteng, de Quesada, Felipe, Rizvi, Mehedi H., Tracy, Joseph B. et al. 2022. "Microscopic dynamics underlying the stress relaxation of arrested soft materials." Proceedings of the National Academy of Sciences, 119 (30).
Version
Final published version
Abstract
Arrested soft materials such as gels and glasses exhibit a slow stress relaxation with a broad distribution of relaxation times in response to linear mechanical perturbations. Although this macroscopic stress relaxation is an essential feature in the application of arrested systems as structural materials, consumer products, foods, and biological materials, the microscopic origins of this relaxation remain poorly understood. Here, we elucidate the microscopic dynamics underlying the stress relaxation of such arrested soft materials under both quiescent and mechanically perturbed conditions through X-ray photon correlation spectroscopy. By studying the dynamics of a model associative gel system that undergoes dynamical arrest in the absence of aging effects, we show that the mean stress relaxation time measured from linear rheometry is directly correlated to the quiescent superdiffusive dynamics of the microscopic clusters, which are governed by a buildup of internal stresses during arrest. We also show that perturbing the system via small mechanical deformations can result in large intermittent fluctuations in the form of avalanches, which give rise to a broad non-Gaussian spectrum of relaxation modes at short times that is observed in stress relaxation measurements. These findings suggest that the linear viscoelastic stress relaxation in arrested soft materials may be governed by nonlinear phenomena involving an interplay of internal stress relaxations and perturbation-induced intermittent avalanches.
Subjects
Multidisciplinary
MIT Department
Massachusetts Institute of Technology. Department of Materials Science and Engineering
Massachusetts Institute of Technology. Department of Mechanical Engineering
Terms of Use
Creative Commons Attribution-NonCommercial-NoDerivs License
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DOI of Published Version
https://doi.org/10.1073/pnas.2201566119
