Correlation between Thermo-mechanical Reliability and Superhydrophobic Nature of CNT Composite Coatings

One of the most important applications for superhydrophobic coatings is anti-frosting for safety and energy conservation. Safety concerns are especially critical in cold-climate regions where the daily temperature fluctuation is large. However, superhydrophobic coatings have not been studied in terms of their thermomechanical reliability. In this study, wetting characteristics and stress relaxation behavior were quantitatively investigated with multi-walled carbon nanotube (MWNT)–silicone composite films under thermal cycling condition. It is concluded that an open structure with numerous nanopores among the fillers, constituting air pockets described as the “Cassie structure,” is of great importance not only for developing a film's superhydrophobic nature but also for accommodation of thermal stress that evolved from different coefficients of thermal expansion between the coating and the substrate. The amount of stress relaxation for a 30 vol% MWNT–silicone composite film with open structure reaches ~80%...