(305b) Topographical Defects Can Confer Exceptional Ice Nucleation Ability to Mediocre Nucleants

Heterogeneous ice nucleation at solid substrates or induced by the presence of ice-nucleating particles is of great importance to many fields of science and engineering. Although recent advance molecular simulations and image-based experimental techniques provide opportunities to investigate the underlying mechanisms of ice formation, we still have limited knowledge of how the heterogeneous chemistry of the surfaces, particularly in the form of topographical defects, geometry, different crystal faces, and chemical irregularities. In the present study, we use molecular dynamics simulation and the classical nucleation theory to investigate the freezing behavior of water on the cholesterol monohydrate surface with an angle of the step. We identify that the special topography of the ice-nucleating interfaces can make mediocre nucleates become exceptional ones. The corresponding special geometries are those that accommodate ice nuclei without introducing strain to ice. This confirms that topographical defects of ice-nucleating surfaces are responsible for the experimental distribution of ice freezing temperatures induced by cholesterol monohydrate. Our work provides predictive understanding of the role of topography features on nucleation for ice and other crystals in general.