Vapor-based synthesis of bilayer anti-corrosion polymer coatings with excellent barrier property and superhydrophobicity

Bilayer polymer coatings that consisted of a highly cross-linked polyethylene glycol diacrylate (PEGDA) bottom layer and nanostructured poly(perfluorodecyl acrylate- co -ethylene glycol diacrylate) (P(PFDA- co -EGDA)) top layer were synthesized via a single-step vapor deposition method. The vapor-synthesized PEGDA single-layer film exhibits excellent barrier performance with oxygen permeability of 0.0066 Barrer, which is more than 16-fold smaller than that of commercial PET packaging film. The P(PFDA- co -EGDA) layer, grown on top of PEGDA, shows conical array structure. Such nanostructure combined with the low surface energy of PFDA moiety enables superhydrophobicity of the coating with water contact angle of 159°. The achieved superhydrophobicity is stable over more than 168 h upon immersion in NaCl solution. The bilayer coating structure imparts a synergistic effect to minimize both the diffusion of water and ions and permeation of oxygen, resulting in a significant drop of corrosion rate to 2.19 × 10 −7 mm year −1 , a more than 10 4 -fold decrease compared to bare copper.