Center for Creative Convergence Research, Korea Research Institute of Standards and Science (KRISS), Daejeon, 34113, Republic of Korea.
Department of Nano Science, University of Science and Technology, Daejeon, 34113, Republic of Korea.
Small. 2020 Mar;16(11):e1907478. doi: 10.1002/smll.201907478. Epub 2020 Feb 12.
Colloidal crystallization is analogous to the crystallization in bulk atomic systems in various aspects, which has been explored as a model system. However, a real-time probing of the phenomenon still remains challenging. Here, a levitation system for a study of colloidal crystallization is demonstrated. Colloidal particles in a levitated droplet are gradually concentrated by isotropic evaporation of water from the surface of the droplet, resulting in crystallization. The structural change of the colloidal array during crystallization is investigated by simultaneously measuring the volume and reflectance spectra of the droplet. The crystal nucleates from the surface of the droplet at which the volume fraction exceeds the threshold and then the growth proceeds. The crystal growth behavior depends on the initial concentrations of colloidal particles and salts which determine the overall direction of crystal growth and interparticle spacing, respectively. The results show that a levitating bulk droplet has a great potential as a tool for in situ investigation of colloidal crystallization.
胶态结晶在各个方面类似于体相原子系统中的结晶，已被探索作为模型体系。然而，对该现象的实时探测仍然具有挑战性。在这里，展示了一种用于胶体结晶研究的悬浮系统。通过从液滴表面各向同性蒸发水，使悬浮液滴中的胶体颗粒逐渐浓缩，从而导致结晶。通过同时测量液滴的体积和反射率谱来研究胶体阵列在结晶过程中的结构变化。在体积分数超过阈值的液滴表面开始成核，然后进行生长。晶体的生长行为取决于胶体粒子和盐的初始浓度，它们分别决定了晶体生长的总体方向和粒子间的间距。结果表明，悬浮的体相液滴具有作为胶体结晶原位研究的工具的巨大潜力。
