Fabricating superhydrophobic surfaces via coating amine-containing fluorinated emulsion and Michael addition reaction

In this work, highly fluorinated acrylate emulsions with reliable stability emulsified by protonated octadecylamine were successfully synthesized. With appropriate protonation, the obtained emulsion showed high monomer conversions up to 90.2% and ultralow surface energy. The ultralow-surface-energy coatings were fabricated via surface enrichment of abundant fluorine and replacing hydrophilic amino groups with hydrophobic groups through the Michael addition reaction. Superhydrophobic and self-cleaning surfaces were prepared on porous substrates through dip coating. When fabricated on porous glass fiber nonwoven mats, surfaces coated with enriching fluorinated side chains and few hydrophilic groups showed remarkable superhydrophobicity with a water contact angle more than 150º and a low sliding contact angle of 4.7°. The usage of fluorinated emulsions was sharply reduced due to the addition of perfluorinated acrylate. Moreover, the Michael acceptors were alternative such as perfluorinaed acrylates, long aliphatic acrylates and crosslinking acrylates, displaying superior hydrophobicity and waterproof properties. All the results conclusively indicated that this practical modified method was promising for potential applications of hydrophobic modifications.