Direct Visualization of Molecular Stacking in Quasi-2D Hexagonal Ice.

Understanding ice nucleation and growth is of great interest to researchers due to its importance in the biological, cryopreservation, and environmental fields. However, microstructural investigations of ice on the molecular scale are still lacking. In this paper, a simple method is proposed to prepare quasi-2-dimensional ice I films, which have been characterized via cryogenic transmission electron microscope. The intersecting stacking faults of basal (BSF) and prismatic (PSF) types have been directly visualized and resolved with a notable first-time report of PSF in ice I. Moreover, the possible growth pathways of BSF, namely, the I phase, were elucidated by the theoretical calculations and the chair conformation of HO molecules. This study offers valuable insights that can enhance researchers' understanding of the growth kinetics of crystalline ice.