Interfacial undercooling in solidification of colloidal suspensions: analyses with quantitative measurements.
Interfacial undercooling in solidification of colloidal suspensions: analyses with quantitative measurements.
复制标题
胶体悬浮液凝固中的界面过冷：定量测量分析
DOI：
10.1038/srep28434
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发表时间：
2016-06-22
影响因子：
4.6
通讯作者：
Huang W
中科院分区：
文献类型：
--
作者：
You J;Wang L;Wang Z;Li J;Wang J;Lin X;Huang W
胶体悬浮体复杂凝固过程中的界面过冷度具有重要意义，但仍然是一个令人困惑的问题。两种类型的界面过冷度被认为涉及胶体悬浮液的冷冻，即，溶剂中添加剂引起的溶质组成过冷（SCS）和颗粒引起的颗粒组成过冷（PCS）。然而，胶体悬浮体的凝固中的界面过冷度的定量识别，仍然是缺席的，因此，在这个复杂的系统中，哪种类型的过冷度是占主导地位的问题仍然没有答案。在这里，我们定量测量了静态和动态的界面过冷度SCS和PCS在理想和实际的胶体系统。结果表明，界面过冷度主要来源于溶剂中添加剂引起的SCS，而PCS是次要的。这一发现意味着，从PCS的颗粒的热力学效应是不是基本的物理机制的图案形成的细胞生长和层状结构的胶体悬浮液的固化，冰模板法的一般情况下。相反，可以通过调节添加剂来有效地控制冰模板法中的图案。
Interfacial undercooling in the complex solidification of colloidal suspensions is of significance and remains a puzzling problem. Two types of interfacial undercooling are supposed to be involved in the freezing of colloidal suspensions, i.e., solute constitutional supercooling (SCS) caused by additives in the solvent and particulate constitutional supercooling (PCS) caused by particles. However, quantitative identification of the interfacial undercooling in the solidification of colloidal suspensions, is still absent; thus, the question of which type of undercooling is dominant in this complex system remains unanswered. Here, we quantitatively measured the static and dynamic interface undercoolings of SCS and PCS in ideal and practical colloidal systems. We show that the interfacial undercooling primarily comes from SCS caused by the additives in the solvent, while PCS is minor. This finding implies that the thermodynamic effect of particles from the PCS is not the fundamental physical mechanism for pattern formation of cellular growth and lamellar structure in the solidification of colloidal suspensions, a general case of ice-templating method. Instead, the patterns in the ice-templating method can be controlled effectively by adjusting the additives.