表面能对冰晶形貌的影响

本工作从介科学概念出发,提出了表面能对冰晶生长形貌调控的科学假设.通过在水中添加不同添加剂(蔗糖、氯化钠、表面活性剂SDS),改变水溶液的表面张力,利用激光共聚焦显微镜原位实验装置开展了冰晶生长动力学研究.结果 表明,在相同过冷度条件下,随溶液表面张力降低,冰晶形貌由具有对称性的枝状变为无序的海藻晶,这种变化在不同溶液...

Role of surface energy in the formation of ice morphology

The icing phenomenon is ubiquitous in nature, from the formation of snowflakes to the low-temperature preservation of food to the anti-icing of aircraft wings. It is both a scientific and technological interest to understand and control the morphology of ice crystals. Inspired by the concept of mesoscience, this study raises the scientific hypothesis that surface energy plays an important role in the morphology evolution of ice crystals. To regulate the surface energy, different additives (sucrose, sodium chloride, and surfactant SDS) were added to the aqueous solution, and the icing processes with different surface tensions was observed by a homemade cooling device loaded at a laser confocal microscope. It was found that the morphologies of ice crystals transfer from dendritic with good symmetry to disordered seaweed crystals with the decrease of the surface tension at the same undercooling conditions, and this change was verified in different kinds of solutions. Further investigations showed that the lower surface tension of the solution resulted in a change of growth rate of ices in the solution. At high growth rates, the growing surface of ice crystals became unstable, and the crystal plane grew anisotropically, resulting in the formation of dendrite structures. However, at low growth rates, the growth surface of ice crystals was covered by additive molecules. The anisotropy of the crystal plane disappears, and hence a disordered dendrite structure was formed. The above findings confirmed the dominant role of supercooling and surface energy in the growth of the material structure, which provides experimental proof to evaluate the concept of mesoscience.