Interfacial Characteristics of Ice-Supporting Substrates via Molecular Dynamics Simulations

Ice accretion on critical infrastructure and equipment, including aircraft, wind turbines, solar panels, and power lines, poses significant risks to operational safety and incurs substantial economic losses annually.¹ Traditional active de-icing methods, such as mechanical vibration, thermal heating, and chemical spraying, have demonstrated efficacy but suffer from drawbacks including high energy consumption, environmental concerns, and operational inefficiencies.² Consequently, there has been a shift towards exploring passive anti-icing solutions, such as icephobic coatings, which offer an environmentally friendly and energy-independent means to mitigate ice formation and facilitate its removal. These coatings, by reducing ice adhesion strength to below critical thresholds, enable ice shedding through natural forces like wind and gravity.³<br/>The present work focuses on characterizing the low ice adhesion properties of various substrates through molecular descriptors. We follow the hypothesis that has been previously speculated in several experimental works^4,5 according to which a disordered, liquid-like layer (QLL) of water at the substrate/ice interface is developed, which in turn acts as a self-lubricant reducing the ice adhesion strength and enhancing the material’s icephobicity. To put this idea into the test, we conducted exhaustive molecular dynamics (MD) simulations on ice, supported by different types of substrates, such as graphite, a boron nitride sheet, and a cross-linked polymer epoxy matrix. Our findings reveal that the ice structure becomes disordered near the interface for all substrates, with a more pronounced effect in the polymer substrate. Detailed analysis showed that this is directly correlated to the development of hydrogen bonds between the interfacial water molecules and the polymer substrate’s polar atoms, which was found to induce a more intense disruption of interfacial ice’s crystal structure, promoting thus the formation of a thicker QLL. Our detailed analysis showed that there are specific atoms of the polymer substrate that interact more intensively with the water molecules of the crystal ice, providing thus important guidance towards the fabrication of polymer coatings that exhibit the necessary nanoscale chemical formulae that can result in very low ice adhesion strengths.<br/><br/>1. He, Z.; Zhuo, Y.; Zhang, Z.; He, J., <i>Coatings</i> <b>2021</b>, <i>11</i>.<br/>2. Freeman, A. I.; Surridge, B. W. J.; Matthews, M.; Stewart, M.; Haygarth, P. M., <i>Environmental Technology & Innovation </i><b>2015</b>, <i>3</i>.<br/>3. Golovin, K.; Tuteja, A.. <i>Science Advances</i> <b>2017</b>,<i> 3</i>.<br/>4. Chen, D.; Gelenter, M. D.; Hong, M.; Cohen, R. E.; McKinley, G. H., <i>ACS Applied Materials & Interfaces </i><b>2017</b>, <i>9</i>.<br/>5. Chen, J.; Dou, R.; Cui, D.; Zhang, Q.; Zhang, Y.; Xu, F.; Zhou, X.; Wang, J.; Song, Y.; Jiang, L., <i>ACS Applied Materials & Interfaces </i><b>2013</b>.