Routes to cubic ice through heterogeneous nucleation

Area of Science:

• Physical Sciences
• Materials Science
• Crystallography

Background:

• The crystallization of water into ice is fundamental but not fully understood at the molecular level.
• Distinguishing between cubic ice (Ice Ic) and hexagonal ice (Ice Ih) formation is a key area of debate.
• Recent advancements have enabled laboratory synthesis of pure Ice Ic, raising questions about its formation from liquid water.

Purpose of the Study:

• To investigate the heterogeneous nucleation of different ice polytypes from liquid water.
• To identify factors governing the selective formation of cubic ice (Ice Ic) over hexagonal ice (Ice Ih).
• To explore substrate design principles for controlling ice polymorphism.

Main Methods:

• Conducted a high-throughput computational screening study.
• Utilized molecular dynamics simulations for nucleation on over 1,100 model substrates.
• Analyzed the water contact layer's structure and its resemblance to ice faces.

Main Results:

• Numerous substrates can promote the formation of pristine cubic ice (Ice Ic).
• Cubic ice (Ice Ic) can be selectively nucleated even under mild supercooling conditions.
• The key factor for polytype selectivity and nucleation temperature is the water contact layer's resemblance to an ice face, not substrate lattice match.
• Substrate lattice match to ice does not predict the resulting polytype.

Conclusions:

• Heterogeneous nucleation significantly influences ice I polytypism.
• The study provides insights into controlling polymorphism and stacking disorder in materials.
• Identified pathways for the formation of cubic ice (Ice Ic) from liquid water.