Preparation of superhydrophobic asymmetric vitrimer coating with high porosity and the key role of hierarchical pocket structure on long freeze delay time and high durability

It is still a big challenge to prepare superhydrophobic anti-icing coatings with long freeze delay performance and high durability. In this work, in different with conventional flexible porous coating, we prepared an asymmetric coating with hierarchical pocket structure by a facile hot-pressing/salt-leaching (BHS) method on a polyacrylate vitrimer polymer with mellability. The asymmetric architecture endowed porous coating with low density and high adhesion strength. The in-situ growth of silica nanoparticles in above porous coating and surface modification generated a superhydrophobic hierarchical pocket structure. As a result, the freezing delay time was drastically increased to 14,400 s at −10°C. Furthermore, owing to hierarchical pocket structure, the coating could maintain its superhydrophobicity and anti-icing performance under water flow impacting at 10 kPa pressure, 30 cycles of sandpaper abrasion, 50 cycles of tape peeling, showing advantageous high durability. By employing the hierarchical porous coating on heat exchangers, the energy consumption was drastically reduced by 93%.