Ice nucleation is important in global climate change and could also have implications to nucleation of more complex systems like clathrate hydrates. A new setup for experimental investigations of nucleation of ice that uses linear cooling ramps is described. The nucleation rates of ice in (1) microliter–sized quasi–free water droplets suspended at an interface between an inert fluorocarbon oil, perfluoromethyldecalin, and an inert hydrocarbon oil, squalane, and (2) microliter–sized quasi–free water droplets supported by stable wetting films of squalane, were determined from the procedure that was previously developed for clathrate hydrates. The impact of the number of the data points and the experimental cooling rate was investigated in detail. The nucleation curve of a given system was found to remain largely unchanged with the addition of data after about the first 100 data points. Additional 300 to 400 data points confirmed such convergence. The results also showed that the nucleation rate increased with the system supercooling, as expected, and the whole nucleation curve shifted somewhat downward with the use of a slower cooling rate. The nucleation rates of ice in the water droplets supported by stable wetting films of squalane were broadly similar to but slightly greater than those suspended between two immiscible liquids. We then compared our data to the nucleation rate of ice reported in the literature, which showed broad agreements when the differences in the scales were accounted for. The experimental method described was found to be reliable and the setup provides a basis for future studies on ice nucleation that may involve nucleation promoters, inhibitors or more complex entities.

冰核化在全球气候变化中很重要，也可能对像笼形水合物这样的更复杂系统的核化产生影响。描述了一种使用线性冷却坡道进行冰成核实验研究的新装置。悬浮在惰性碳氟油，全氟甲基萘烷和惰性烃油，角鲨烷之间的界面上的（1）微升准准水滴中的冰成核率，以及（2）支持的微升准准水滴中的冰成核率角鲨烷的稳定润湿膜是由先前为包合物水合物开发的程序确定的。详细研究了数据点数量和实验冷却速率的影响。发现在大约前100个数据点添加数据后，给定系统的成核曲线基本保持不变。另外300到400个数据点证实了这种收敛。结果还表明，如预期的那样，随着系统的过冷，成核速率增加，并且在使用较低的冷却速率时，整个成核曲线有些向下移动。由角鲨烷的稳定润湿膜支撑的水滴中冰的成核速率与悬浮在两种不混溶液体之间的悬浮液的成核速率大致相似，但略大。然后，我们将我们的数据与文献中报道的冰的成核速率进行了比较，当考虑到尺度差异时，冰的成核速率显示出广泛的一致性。