Three-dimensional imaging of colloidal glasses under steady shear
Three-dimensional imaging of colloidal glasses under steady shear
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DOI：
10.1103/physrevlett.99.028301
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发表时间：
2007-07-13
影响因子：
8.6
通讯作者：
Poon, W. C. K.
中科院分区：
文献类型：
--
作者：
Besseling, R.;Weeks, Eric R.;Poon, W. C. K.
使用快速共聚焦显微镜，我们图像的三维动力学的颗粒在一个产生的硬球胶体玻璃下稳定剪切。在均匀剪切区域观察到的结构弛豫几乎是各向同性的，但与静态亚稳胶体流体的结构弛豫明显不同。反弛豫时间τ（-1）（alpha）和扩散常数D作为局部剪切速率（gamma）对点的函数，显示出显著的剪切稀化，其中τ（-1）（alpha）与D成比例，与（gamma）对点成比例（0.8），超过二十年（gamma）对点。相反，系统的整体流变性表现为Herschel-Bulkley行为。我们讨论了大规模剪切本地化和其他机制在产生这种差异的可能作用。
Using fast confocal microscopy we image the three-dimensional dynamics of particles in a yielded hard-sphere colloidal glass under steady shear. The structural relaxation, observed in regions with uniform shear, is nearly isotropic but is distinctly different from that of quiescent metastable colloidal fluids. The inverse relaxation time tau(-1)(alpha) and diffusion constant D, as functions of the local shear rate (gamma) over dot, show marked shear thinning with tau(-1)(alpha)proportional to D proportional to (gamma) over dot(0.8) over more than two decades in (gamma) over dot. In contrast, the global rheology of the system displays Herschel-Bulkley behavior. We discuss the possible role of large scale shear localization and other mechanisms in generating this difference.