Concentrated suspensions of Brownian beads in water: dynamic heterogeneities trough a simple experimental technique
| Autor: | Marco Caggioni, Francesco Greco, Raffaele Pastore, Domenico Larobina, Luigi Santamaria Amato |
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| Přispěvatelé: | Pastore, R., Caggioni, M., Larobina, D., Santamaria Amato, L., Greco, F. |
| Rok vydání: | 2019 |
| Předmět: |
Length scale
General Physics and Astronomy FOS: Physical sciences Condensed Matter - Soft Condensed Matter Tracking (particle physics) 01 natural sciences Physics - Chemical Physics 0103 physical sciences glass transition Statistical physics 010306 general physics Supercooling 010303 astronomy & astrophysics Condensed Matter - Statistical Mechanics structural relaxation Brownian motion Physics Chemical Physics (physics.chem-ph) Condensed Matter - Materials Science Statistical Mechanics (cond-mat.stat-mech) Materials Science (cond-mat.mtrl-sci) Characterization (materials science) dynamic heterogeneitie Particle Relaxation (physics) Soft Condensed Matter (cond-mat.soft) colloidal glasse Focus (optics) |
| DOI: | 10.48550/arxiv.1904.01865 |
| Popis: | Concentrated suspensions of Brownian hard-spheres in water are an epitome for understanding the glassy dynamics of both soft materials and supercooled molecular liquids. From an experimental point of view, such systems are especially suited to perform particle tracking easily, and, therefore, are a benchmark for novel optical techniques, applicable when primary particles cannot be resolved. Differential Variance Analysis (DVA) is one such novel technique that simplifies significantly the characterization of structural relaxation processes of soft glassy materials, since it is directly applicable to digital image sequences of the sample. DVA succeeds in monitoring not only the average dynamics, but also its spatio-temporal fluctuations, known as dynamic heterogeneities. In this work, we study the dynamics of dense suspensions of Brownian beads in water, imaged through digital video-microscopy, by using both DVA and single-particle tracking. We focus on two commonly used signatures of dynamic heterogeneities: the dynamic susceptibility, $\chi_4$, and the non-Gaussian parameter, $\alpha_2$. By direct comparison of these two quantities, we are able to highlight similarities and differences. We do confirm that $\chi_4$ and $\alpha_2$ provide qualitatively similar information, but we find quantitative discrepancies in the scalings of characteristic time and length scale on approaching the glass transition. Comment: The original publication is available at http://www.scichina.com and http://www.springerlink.com http://engine.scichina.com/publisher/scp/journal/SCPMA/doi/10.1007/s11433-019-9401-x?slug=abstract |
| Databáze: | OpenAIRE |
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