‘‘Aging’’ of the structure of crystals of hard colloidal spheres
‘‘Aging’’ of the structure of crystals of hard colloidal spheres
复制标题
硬胶体球晶体结构的“老化”
DOI：
10.1063/1.480923
复制
发表时间：
2000
影响因子：
4.4
通讯作者：
J. Dhont
中科院分区：
文献类型：
--
作者：
W. Kegel;J. Dhont
我们研究了当重力影响最小且多分散性较小（<3%）时胶体硬球晶体结构的发展。通过在晶体成核过程中施加各种类型的剪切应力，构成晶体的密排六方层的初始堆叠会发生变化。实验粉末衍射图与部分断层孪晶面心立方（fcc）结构一致，该结构以随机堆叠的微晶为代价而生长。如果最初生成故障孪生面心立方结构，则在相当长的时间内不会发现任何变化。目前的观察结果排除了随机堆叠结构是（接近）硬球胶体晶体平衡结构的可能性，并指出了这些系统中断层孪生面心立方晶体的热力学或动力学稳定性。
We study the development of the structure of crystals of colloidal hard spheres in time when gravity effects are minimal and polydispersity is small (<3%). The initial stacking of the close-packed hexagonal layers that make up the crystals is varied by applying various types of shear stress during nucleation of the crystals. The experimental powder diffraction patterns are consistent with a fraction of a faulted-twinned face-centered cubic (fcc) structure that grows at the expense of randomly stacked crystallites. If a faulted-twinned fcc structure is generated initially, no change is found over a considerable time. The present observations rule out the possibility that a randomly stacked structure is the equilibrium structure of colloidal crystals of (nearly) hard spheres, and point to the thermodynamic or kinetic stability of faulted-twinned fcc crystals in these systems.