Ice accumulation on solid surfaces of aircrafts, wind turbines, heat exchange elements, roads and power cables can result in car accidents, malfunctioning of transmission lines, decrease of heat transfer efficiency, impart structural damage and instabilities in wind turbines, and even cause catastrophic aircraft accidents. Tragic examples of flight crashes due to ice build-up and resulting in fatalities include, the Air Florida Flight 90 on January 13, 1982 between Washington D.C. and Arlington, VA, the Air Ontario Flight 1363 on March 10, 1989 In Dryden, Ontario, Canada, the American Eagle Flight 4184 on October 31, 1994 near Roselawn, IN, and more recently the Flight 3407 which crashed in Buffalo, NY. It thus comes as no surprise that significant effort has been expended to develop surfaces that facilitate the removal of ice or retard its formation. The safety and performance of modern aircraft are significantly reduced even by light, scarcely visible ice on airfoils, compression inlets of air-breathing engines, and air flow measurement instruments. Aircraft exterior collide with super-cooled water droplets at altitudes between 2740 and 6100m when flying through cirrus clouds or encountering freezing rain, and the impacting water freezes rapidly to accrete on the aircraft surface. Ice accretion on aircraft surfaces such as leading edges of wings ,propellers, rotor blades, engine intakes results in a dangerous loss of lift force, which causes the aforementioned tragic crash accidents.Current aircraft ice retardation strategies are divided into deicing and anti-icing equipment. Anti-icing equipment is turned on before entering icing conditions and is designed to prevent ice from forming, usually by keeping the temperature above the freezing point. This includes electric thermal heating systems (, anti-ice systems that use hot compressed air that is tapped off the compressor section of the engines to prevent ice from forming on critical engine components such as the air inlet lip and the turbine engine inlet guide vanes. Fluid freeze point depressant systems which are organic liquids whose crystallization temperatures are much lower than that of water are also widely applied on the surface of aircrafts to prevent icing and frosting. Deicing equipment is designed to remove ice after it begins to accumulate on the airframe such as in the case of pneumatic boot systems that expand and contract on ice-prone areas of the aircraft or helicopter. Electric thermal heating systems can decrease flight operating efficiency while fluid freeze point depressants are only effective for short durations and may also cause various environmental problems. A durable, self-lubricating icephobic elastomer coating (SLIC) was realized by systematic optimization of silicone oil infusion levels within a robust, weather-resistant silicone elastomer matrix for ultra-low ice adhesion, targeting high durability levels for a variety of applications operating in harsh icing environments such as in aviation. This coating combines multiple properties that synergistically enhance the ice release effect, i.e., hydrophobicity, low surface roughness, coating elasticity and lubrication enabled interfacial slippage. Supercooled drop impact icing experiments on rotating fan blades at rpms of same order of magnitude as commercial aircraft engines showed that the SLIC repeatedly reduced more ice on the coating than other commercial hydrophobic and superhydrophobic surfaces. In addition, the SLIC displayed long-term self-replenishing lubrication – after repeated mechanical abrasion of the surface, lubricants stored within the bulk of the coating could continuously migrate to the surface to replace the lost lubricants, thus promoting low ice adhesion. Durability tests also showed that the SLIC could withstand long-term micron-sized droplet impact at 25 m/s and acceleration loading up to 276 g without coating degradation. This study is the first to demonstrate a lubricated, self-replenishing coating material capable of repeated ice removal from the coating surface in harsh environmental conditions.
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