Desublimation Frosting on Nanoengineered Surfaces.

Area of Science:

• Materials Science
• Surface Science
• Thermodynamics

Background:

• Ice nucleation from vapor poses challenges in refrigeration, transportation, and energy generation.
• Fabricating intrinsically icephobic surfaces for frost formation via condensation or desublimation remains difficult.

Purpose of the Study:

• Investigate the impact of material composition and surface nanoroughness on frost nucleation and growth.
• Understand frost formation mechanisms within the sublimation domain (0 °C to -55 °C).

Main Methods:

• Studied frost nucleation and growth on silicon surfaces with varying textures.
• Examined conditions within the sublimation domain (0 °C to -55 °C; 6 to 0.02 mbar partial water vapor pressures).
• Utilized nucleation physics principles and Kelvin's equation.

Main Results:

• Desublimation is not the favored frosting pathway on silicon below the homogeneous ice nucleation limit (<-46 °C).
• Surface nanoroughness increases the probability of frost formation on silicon.
• Nanotextures with specific radii of curvature promote frost growth via capillary condensation at low temperatures (-48 °C to -55 °C).

Conclusions:

• Engineered or defect-induced nanoscale surface morphology can be detrimental to frost icephobicity.
• Findings offer fundamental insights into phase transitions in the sublimation domain.
• Implications for designing anti-icing surfaces in critical applications like travel and power generation.