The effect of superhydrophobic coating composition on the topography and ice adhesion

Abstract

Ice accumulation on solid surfaces adversely affects many applications. Among diverse surface modification methods to reduce ice adhesion strength, superhydrophobic (SHP) surfaces have been considered due to their non-wetting characteristics, which minimize the solid-liquid interface, reducing the actual solid-ice contact area. In this work, the shear adhesion strength required for ice removal was studied for a series of thermoplastic-based SHP coatings with a wide particle content range. It was found that particle content plays a complex role in the shear adhesion strength of the coating, which changes the locus of failure for ice removal. The presence of cracks at higher particle loading (above 40 wt%) significantly changed the behavior of the coating, increasing the shear stress for removal. This was attributed to the ice anchoring effect caused by crack formation and penetration of the freezing water into the cracks. To minimize the ice-SHP coating interface shear adhesion, crack formation should be eliminated incorporating the lowest possible NPs content, preserving the Cassie-Baxter wettability state. In the case of the PU nanocomposite coating, 35 and 40 wt% silica NPs coatings demonstrate the optimal result with very low ice adhesion. As crack formation is a common phenomenon in high content NPs nanocomposite coatings, the composition of nanocomposite coatings should be optimized for each material system to minimized crack presence with appropriate surface energetics.