Selective nucleation of ice crystal depending on the inclination angle of nanostructure
Heterogeneous nucleation is decided by many factors, and surface morphology is one of the most important elements. This paper reports the selective ice nucleation and growth process on a series of nanorods with different inclinations, which were rarely mentioned in previous researches. It is found that the nanorods with special inclinations can cause the selective nucleation of ice crystal because of the spatial geometry matching. On this basis, we can regulate the ice crystal types (mainly including cubic ice and hexagonal ice) accordingly, and even improve the freezing efficiency via controlling the inclinations of surface nanorods. In particular, cubic ice occupies the dominant role in the ice crystal on the surface of 45°-inclination nanorods, yet 90°-inclination nanorods are more beneficial to the formation of hexagonal ice. The shape of nanorods not only controls the type of ice crystal, but also changes the freezing efficiency because different ice crystal has unequal nucleation energy barrier. There are no apparent differences among the freezing efficiency on nanostructures with 45°, 75° and 90° inclination nanorods, and the 60°-inclination nanorods are more favorable for ice nucleation. Our studies can promote the understanding on the selective nucleation of ice crystal and provide theoretical basis to achieve the regulation of freezing efficiency.