Thermally conductive superhydrophobic composite coatings with anti-corrosion property

The special wettability coating with self-cleaning and anti-corrosion performance can effectively solve the corrosion and coking problems of heat exchange tube, which has attracted much attention. In this work, hydroxylated boron nitride (OH-BNNS) was prepared from hexagonal boron nitride (H-BN) by liquid-phase exfoliation to improve the thermal conductivity. Different sizes of OH-BNNS, modified aluminum nitride (M-AlN) and polytetrafluoroethylene (PTFE) were added into the epoxy resin (EP) to obtain coating suspension, which was sprayed to successfully prepare M-AlN@OH-BNNS/EP superhydrophobic coatings with the thermal conductivity and anti-corrosion. The superhydrophobic coatings had thermal conductivity of 1.454 ± 0.001 W/(m·K), water contact angle (WCAs) of 160.7 ± 1.4° and water sliding angle (WSAs) of 3.3 ± 0.7°. Moreover, it had good adhesion (1 grade), excellent wear resistance (1000 cycles of sandpaper abrasion), self-cleaning and anti-fouling properties. More importantly, the electrochemical results indicated that the impedance modulus of the superhydrophobic coatings was 9.36 × 10¹⁰ Ω·cm² after soaking 3.5 wt% NaCl for 30 d, showing outstanding corrosion resistance. This study presented the application of superhydrophobic coatings in anti-corrosion and heat conduction.