Edmond Kazem V, Nugent Carolyn R, Weeks Eric R
Physics Department, Emory University, Atlanta, Georgia 30322, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2012 Apr;85(4 Pt 1):041401. doi: 10.1103/PhysRevE.85.041401. Epub 2012 Apr 11.
We study a dense colloidal suspension confined between two quasiparallel glass plates as a model system for a supercooled liquid in confined geometries. We directly observe the three-dimensional Brownian motion of the colloidal particles using laser scanning confocal microscopy. The particles form dense layers along the walls, but crystallization is avoided as we use a mixture of two particle sizes. A normally liquidlike sample, when confined, exhibits slower diffusive motion. Particle rearrangements are spatially heterogeneous, and the shapes of the rearranging regions are strongly influenced by the layering. These rearranging regions become more planar upon confinement. The wall-induced layers and changing character of the spatially heterogeneous dynamics appear strongly connected to the confinement-induced glassiness.
我们研究了一种限制在两个近似平行玻璃板之间的致密胶体悬浮液，将其作为受限几何结构中过冷液体的模型系统。我们使用激光扫描共聚焦显微镜直接观察胶体颗粒的三维布朗运动。颗粒沿着壁形成致密层，但由于我们使用了两种粒径的混合物，所以避免了结晶。一个通常呈液体状的样品在受限情况下表现出较慢的扩散运动。颗粒重排是空间非均匀的，重排区域的形状受到分层的强烈影响。这些重排区域在受限情况下变得更加平面化。壁诱导层以及空间非均匀动力学的变化特征似乎与受限诱导的玻璃化密切相关。
