On Physics of Durable Ice Phobic Surfaces

Icephobic surfaces have a critical footprint on human daily lives ranging from aviation systems and infrastructures to energy systems, but creation of these surfaces for low-temperature applications remains elusive. Non-wetting, liquid-infused and hydrated surfaces have inspired routes for development of icephobic surfaces. However, high freezing temperature, high ice adhesion strength and subsequent ice accretion, low mechanical durability, and high production cost have restricted their practical applications. A comprehensive definition for icephobicity through thermodynamics, heat transfer and mechanics of ice/water-material interface and elucidate physic-based routes was provided through which nano-scale could help to achieve exceptional icephobic surfaces. Here, we cast fundamentals of two new physical concept called magnetic slippery surfaces and stress-localization to develop two new icephobic surfaces with extremely low adhesion and exceptional mechanical, chemical and environmental durability.
In the first concept, we report a new magnetic slippery surface outperforming state-of-the-art icephobic surfaces with an ice formation temperature of -34 °C, 2-3 orders of magnitude higher delay time in ice formation, extremely low ice adhesion strength (~2 Pa), and stability in shear flows up to Reynolds number of 105. In these surfaces, we exploit the magnetic volumetric force to exclude the role of solid-liquid interface in ice formation. We show that these inexpensive surfaces are universal and can be applied to all types of solids (no required micro/nano structuring) with no compromise to their unprecedented properties. In stress localization method, new physical concept and corresponding material paradigm to develop highly durable icephobic materials. These materials utilize stress-localization function to initiate crack at the ice-material interface and consequently minimize ice adhesion on the surface. Stress-localization leads to a shear force at the interface for detachment of ice from the material. The developed concept is implemented in elastomers and the superior icephobicity of these materials compared to state-of-the-art materials is demonstrated. These forms of icephobic materials demonstrate excellent mechanical, chemical and environmental durability with no change of characteristics under extreme air and water shear flows. Furthermore, these icephobic materials does not change the aerodynamic characteristics of airfoils thereby providing a promising solution for aerospace application. In contrast to surface-modified coatings, the icephobicity of these materials is a volumetric property and no degradation in the performance occurs in long-term operation under mechanical loadings. The developed concept of stress-localization reduces adhesion of solids on a material by an order of magnitude with no compromise in mechanical properties. We envision that the developed physical concept opens a rational route to minimize adhesion of any solid species (i.e., ice, gas hydrate, dust, and even bio-species) on a surface with omnipresent application in transportation systems (aviation, cars and vessels), energy/water systems, bio-sciences and even space systems.