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, χ4, and the non-Gaussian parameter, α2. By direct comparison of these two quantities,we are able to highlight similarities and differences. We do confirm that χ4 and α2 provide qualitatively similar information, but we find quantitative discrepancies in the scalings of characteristic time and length scale on approaching the glass transition.
类型: 期刊论文
作者: Raffaele Pastore,Marco Caggioni,Domenico Larobina,Luigi Santamaria Amato,Francesco Greco
来源: Science China(Physics,Mechanics & Astronomy) 2019年10期
年度: 2019
分类: 基础科学,工程科技Ⅰ辑
专业: 材料科学
单位: Department of Chemical,Materials and Production Engineering,University of Naples Federico Ⅱ,Corporate Engineering,The Procter & Gamble Company,Institute for Polymers,Composites and Biomaterials,National Research Council of Italy
分类号: TB30
页码: 37-48
总页数: 12
文件大小: 2005K
下载量: 8
本文来源: https://www.lunwen66.cn/article/1cb2b01512b9b93fca77b89f.html