Shear Thinning and Local Melting of Colloidal Crystals
Shear Thinning and Local Melting of Colloidal Crystals
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DOI：
10.1103/physrevlett.107.138301
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发表时间：
2011-09-19
影响因子：
8.6
通讯作者：
Bechinger, Clemens
中科院分区：
文献类型：
--
作者：
Dullens, Roel P. A.;Bechinger, Clemens
当复杂材料受到外力作用时，会发生剪切稀化和增稠等现象，一般认为这些现象与微观结构的变化密切相关。在这里，我们建立了一个直接的和定量的关系，在胶体晶体的剪切稀化和局部熔化区域的表面积之间的关系，通过使用光学镊子拖动探针粒子通过晶体。我们表明，剪切变稀起源于非线性依赖的局部熔化的表面面积上的拖动速度。我们的观察提供了前所未有的定量证据之间的密切关系的机械性能和微观结构的变化。
Phenomena such as shear thinning and thickening, occurring when complex materials are exposed to external forces, are generally believed to be closely connected to changes in the microstructure. Here, we establish a direct and quantitative relation between shear thinning in a colloidal crystal and the surface area of the locally melted region by dragging a probe particle through the crystal using optical tweezing. We show that shear thinning originates from the nonlinear dependence of the locally melted surface area on the drag velocity. Our observations provide unprecedented quantitative evidence for the intimate relation between mechanical properties and underlying changes in microscopic structure.