Icephobicity and durability assessment of superhydrophobic surfaces: The role of surface roughness and the ice adhesion measurement technique

The durability of anti-wetting properties is of great importance for ensuring long-lasting superhydrophobic and icephobic surfaces that require minimal maintenance and resurfacing. Herein, we fabricated superhydrophobic silicone rubber surfaces having ultra-water repellency and icephobic properties via two industrially applicable methods: micro compression molding (CM) and atmospheric pressure plasma (APP) treatment. We produced surfaces covered by micro-nanostructures of differing sizes. We evaluated the anti-icing properties (delayed ice formation) and de-icing properties (reduced ice adhesion strength) of the produced surfaces that were subjected to two forms of icing conditions. The well-known ice adhesion measurement techniques, i.e., the centrifuge adhesion and push-off tests, provided quantitative comparisons of the ice adhesion strength of the produced surfaces. We observed two different mechanical deformations during the ice detachment from the surfaces. Although both superhydrophobic surfaces reduced ice adhesion strength, the smaller surface micro-nanostructures produced a greater reduction in ice adhesion by favoring less ice interlocking with the surface asperities. To rigorously assess the durability of the produced surfaces, we carried out a comprehensive series of experiments that covered a wide range of real-life conditions. Under harsh environmental conditions, the surfaces maintained a water contact angle and contact angle hysteresis of > 150 and < 10, respectively, thereby confirming the resistance of the superhydrophobic silicone surfaces to severe chemical and mechanical damage. In some cases where water repellency was lost, the silicone rubber surfaces demonstrated a satisfactory recovery of their anti-wetting properties.