Transport coefficients and mechanical response in hard-disk colloidal suspensions  

作　　者：张博凯 李健 陈康 田文得 马余强 

机构地区：[1]National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University [2]Department of Physics, Nanjing Normal University [3]Center for Soft Condensed Matter Physics & Interdisciplinary Research, College of Physics,Optoelectronics and Energy, Soochow University

出　　处：《Chinese Physics B》2016年第11期107-113,共7页中国物理B（英文版）

基　　金：Project supported by the National Basic Research Program of China(Grant No.2012CB821500);the National Natural Science Foundation of China(Grant Nos.21374073 and 21574096)

摘　　要：We investigate the transport properties and mechanical response of glassy hard disks using nonlinear Langevin equation theory.We derive expressions for the elastic shear modulus and viscosity in two dimensions on the basis of thermalactivated barrier-hopping dynamics and mechanically accelerated motion.Dense hard disks exhibit phenomena such as softening elasticity,shear-thinning of viscosity,and yielding upon deformation,which are qualitatively similar to dense hard-sphere colloidal suspensions in three dimensions.These phenomena can be ascribed to stress-induced ＂landscape tilting＂.Quantitative comparisons of these phenomena between hard disks and hard spheres are presented.Interestingly,we find that the density dependence of yield stress in hard disks is much more significant than in hard spheres.Our work provides a foundation for further generalizing the nonlinear Langevin equation theory to address slow dynamics and rheological behavior in binary or polydisperse mixtures of hard or soft disks.We investigate the transport properties and mechanical response of glassy hard disks using nonlinear Langevin equation theory.We derive expressions for the elastic shear modulus and viscosity in two dimensions on the basis of thermalactivated barrier-hopping dynamics and mechanically accelerated motion.Dense hard disks exhibit phenomena such as softening elasticity,shear-thinning of viscosity,and yielding upon deformation,which are qualitatively similar to dense hard-sphere colloidal suspensions in three dimensions.These phenomena can be ascribed to stress-induced ＂landscape tilting＂.Quantitative comparisons of these phenomena between hard disks and hard spheres are presented.Interestingly,we find that the density dependence of yield stress in hard disks is much more significant than in hard spheres.Our work provides a foundation for further generalizing the nonlinear Langevin equation theory to address slow dynamics and rheological behavior in binary or polydisperse mixtures of hard or soft disks.

关 键 词：suspensions viscosity rheological Langevin spheres modulus colloidal dimensions elasticity yielding 

分 类 号：O37[理学—流体力学]