Robust and Chemically Stable Superhydrophobic Composite Ceramic Coating Repellent Even to Hot Water

Robust and chemically stable superhydrophobic composite ceramic coating with internal porous structures and superficial network structures has been successfully prepared through incorporating spray and pore-forming technique. The internal micro-/nanoporous structures are regulated by using H2O as pore-forming agent and the superficial network structures are designed by the fibrillated polytetrafluoroethylene (PTFE). Carbon nanotubes (CNTs) modified by dopamine are used to overcome the brittleness of ceramic. The prepared superhydrophobic ceramic/CNT/PTFE coating demonstrates a high water contact angle of 161 degrees +/- 1.2 degrees and low sliding angle of 4 degrees +/- 0.3 degrees. Simultaneously, compared with the pure ceramic coating, the abrasion losses of the prepared coating decrease obviously from 0.0842 to 0.0529 g after the 50 000 friction cycles. The potentiodynamic polarization of the prepared coating demonstrates a significant shift of corrosion potential to the positive direction from -541 to -388 mV and the bending strength increases from 435 to 490 MPa. Moreover, the prepared coating not only possesses excellent hot-water-repellent (99 degrees C) capability but also can withstand high speed water jetting (20 m s(-1)), which is more than two times of the heavy rain velocity (7-9 m s(-1)). Therefore, this promising superhydrophobic ceramic coating may have great application potential in many industrial applications.