Interfacial Characteristics of Ice-Supporting Substrates via Molecular Dynamics Simulations

Area of Science:

• Materials Science
• Physical Chemistry
• Surface Science

Background:

• Ice accumulation on aircraft surfaces presents significant safety and performance challenges.
• Developing effective anti-icing coatings relies on understanding ice adhesion mechanisms at interfaces.

Purpose of the Study:

• To investigate the hypothesis of a disordered, quasi-liquid layer (QLL) at the ice-substrate interface acting as a lubricant.
• To characterize interfacial water properties and their correlation with ice adhesion strength on different substrates.

Main Methods:

• Extensive molecular dynamics (MD) simulations were performed on ice interacting with graphite, boron nitride, and a cross-linked epoxy polymer.
• Analysis included local density, Q6 order parameter, hydrogen bonding, and interfacial water dynamics.

Main Results:

• Ice structure disorder and QLL formation were observed at all interfaces, with a more pronounced effect on the polymer substrate.
• The polymer substrate exhibited a thicker QLL, correlated with increased hydrogen bonding between water and polar substrate atoms.
• Interfacial water mobility was significantly reduced on the epoxy, followed by boron nitride, and least on graphite.

Conclusions:

• The formation of a QLL is a key mechanism for reducing ice adhesion strength, particularly on polymer surfaces.
• Surface chemistry, specifically the presence and type of polar groups (e.g., -OH), significantly influences QLL thickness and icephobic behavior.
• Understanding these interfacial dynamics is crucial for designing advanced ice-preventing coatings.