Competition between heterogeneous and homogeneous nucleation near a flat wall
Competition between heterogeneous and homogeneous nucleation near a flat wall
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DOI：
10.1088/0953-8984/21/46/464115
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发表时间：
2009-10
期刊：
影响因子：
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通讯作者：
P. Wette;A. Engelbrecht;R. Salh;I. Klassen;Dirk Menke;D. Herlach;S. Roth;H. Schöpe
中科院分区：
文献类型：
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作者：
P. Wette;A. Engelbrecht;R. Salh;I. Klassen;Dirk Menke;D. Herlach;S. Roth;H. Schöpe
我们研究了靠近容器壁的带电胶体球水悬浮液的非均相成核和均相成核之间的竞争。平衡晶体结构试样剪切熔化，亚稳熔体在剪切停止后凝固。利用时间分辨散射技术监测结晶动力学：在低颗粒数密度下，我们采用了改进的静态光散射方法，而在大颗粒浓度下，我们首次采用了超小角x射线散射方法。我们的结果显示了一些意想不到的行为：与均匀体形核相比，容器壁上的非均相形核延迟，其速率密度出人意料地略小，表明观察到的结晶过程的复杂性。
We studied the competition between heterogeneous and homogeneous nucleation of an aqueous suspension of charged colloidal spheres close to the container walls. Samples of equilibrium crystalline structure were shear-melted and the metastable melt left to solidify after the cessation of shear. The crystallization kinetics was monitored using time-resolved scattering techniques: at low particle number densities n we applied an improved static light scattering method while at large particle concentrations ultra-small-angle x-ray scattering was applied for the first time. Our results show some unexpected behavior: the heterogeneous nucleation at the container walls is delayed in comparison to the homogeneous bulk nucleation and its rate density appears surprisingly slightly smaller, demonstrating the complexity of the observed crystallization process.