Anti-Icing Superhydrophobic Surfaces: Controlling Entropic Molecular Interactions to Design Novel Icephobic Concrete

Abstract

Abstract:Tribology involves the study of friction, wear, lubrication, and adhesion, including biomimetic superhydrophobic and icephobic surfaces. The three aspects of icephobicity are the low ice adhesion, repulsion of incoming water droplets prior to freezing, and delayed frost formation. Although superhydrophobic surfaces are not always icephobic, the theoretical mechanisms behind icephobicity are similar to the entropically driven hydrophobic interactions. The growth of ice crystals in saturated vapor is partially governed by entropically driven diffusion of water molecules to definite locations similarly to hydrophobic interactions. The ice crystal formation can be compared to protein folding controlled by hydrophobic forces. Surface topography and surface energy can affect both the icephobicity and hydrophobicity. By controlling these properties, micro/nanostructured icephobic concrete was developed. The concrete showed ice adhesion strength one order of magnitude lower than regular concrete and could repel incoming water droplets at´5˝C. The icephobic performance of the concrete can be optimized by controlling the sand and polyvinyl alcohol fiber content.

Scalable and durable polymeric icephobic and hydrate-phobic coatings

“…23 Over the last two decades, there has been significant progress in research and development of surfaces that are icephobic (to varying extents) according to these definitions. 14,21,[24][25][26][27][28][29][30][31][32][33][34][35] Many recent reports have targeted low ice adhesion strength as the primary characteristic used for definition and optimization of icephobic surfaces. 21,[23][24][25][26][31][32][33] While surfaces with low ice adhesion strength have been developed, a major concern is that they lack mechanical robustness and durability as well as scalability for production at large scale.…”

“…14,21,[24][25][26][27][28][29][30][31][32][33][34][35] Many recent reports have targeted low ice adhesion strength as the primary characteristic used for definition and optimization of icephobic surfaces. 21,[23][24][25][26][31][32][33] While surfaces with low ice adhesion strength have been developed, a major concern is that they lack mechanical robustness and durability as well as scalability for production at large scale. 23,31,34,[36][37][38] Recently some durable icephobic surfaces have been developed which use bilayer polymer coatings, 39 elastomeric coatings, 30 chemically-bonded 2D polymer, 40 and PTFE coatings.…”

A survey of icephobic coatings and their potential use in a hybrid coating/active ice protection system for aerospace applications

“…functionalization (similar to superhydrophobic coatings based on the lotus leaf design) and infusing low surface energy polymeric matrices with functional lubricants (similar to slippery surfaces based on the Nepenthes pitcher plant design) [34]. For modelling ice adhesion to a smooth substrate, one can consider that the bonding strength on the atomic/molecular level depends upon three basic forces: electrostatic forces, covalent/chemical bonds, and van der Waals interactions [3]. The dielectric constant of a material affects the electrostatic attractive force; also, ice adhesion has been found to decrease with the dielectric constant of the surface material [35].…”

“…"De icing" refers to the removal of ice from aircraft surfaces and its methods include heating, vibration (contact or non contact), mechanical means (e.g., inflated boots on aircraft leading edges) and sprayed icing fluids [2] to remove any ice accretion, while "anti icing" is a preventive measure that delays or reduces ice accretion on surfaces so that the subsequent de icing process is not needed or less time/energy will be needed during de icing. Anti icing can be achieved by frequent spraying of anti freezing fluids or by the application of permanent coatings (hydro phobic or icephobic), designed to prevent water droplets from adhering to the surface before freezing, to delay the freezing event, and/or to reduce ice adhesion to the surface [3]. The use of de icing fluids for de icing and anti icing purposes has a severe environmental impact [4,5], while a permanent, long lasting coating can lessen such consequence.…”

From Extremely Water-Repellent Coatings to Passive Icing Protection—Principles, Limitations and Innovative Application Aspects

“…Although each of the above mentioned potential real-life applications of super-nonwetting coatings has its significance and importance, the possibility for passively preventing (with no external energy applied) the ice and snow accumulation in harsh environments stands out as an approach with extremely high economic and societal impact [39][40][41][42][43][44]. The reason for such a statement is simple and associated with the detrimental effect of icing on many industrial and social sectors including aviation [42], renewable energy production [44], power and chemical plants [45,46], road infrastructure [41,43], overhead lines [47], solar panels, off-shore oil platforms [44] and many more. Virtually, the icing is undesirable literally everywhere in our daily routine, except may be in the restaurant industry, where the ice cubes are used to cool the beverages.…”