Durable superhydrophobic coating by radiation curing

 
Superhydrophobic (SH) coatings have been applied for easy-cleaning, reduced friction, anti-adhesion and anti-ice etc. Superhydrophobicity is commonly obtained by low surface energy chemistry tailored with nano/micro roughness. Durability of SH surfaces is crucial. Consequently, radiation induced radical reaction was used by Nanto for covalently bonding SiO2 nanoparticles to polymer coatings to obtain durable roughness. The radiation chemistry resulted in durable SH surfaces having high contact angles (>155°) and low sliding angles (<5°). The icephobic characteristics were studied using various substrates. Thus, supercooled water drops bounced back when impinging on SH polycarbonate substrate and froze on SH copper substrate held at -10 to -30°C. Ice shear adhesion (at -20°C) demonstrated reduced shear adhesion to SH treated substrates having low thermal expansion coefficient metals and high thermal expansion coefficient plastics. Hence, the thermal mismatch between the adhering ice and the substrates affect the adhesion strength of the ice to the respective substrate.