A facile and effective approach for the synthesis of fluorinated waterborne polyurethanes with good hydrophobicity and antifouling properties

Due to its nontoxicity and eco-friendliness, waterborne polyurethane (WPU) has attracted increasing attention for use in various industrial applications. To ensure dispersal or dissolution in water, the molecular structures of most WPUs contains ionic groups. Dried WPU films, however, are generally hydrophilic and have a limited application range. To confer high hydrophobicity and antifouling properties to WPU, the incorporation of a fluorocarbon chain into WPU is an efficient approach. Herein, we present a facile and effective approach for synthesizing a novel WPU with a fluorinated side group, a key aspect of which is the preparation of dihydroxy-terminated 1,1,2,2-tetrahydroperfluorodecyl methacrylate (FDMA(OH)2) by a thiol-ene "click" reaction. A chain extender rich in fluorinated side groups is then adapted specifically to an OCN-terminated WPU prepolymer to obtain fluorinated waterborne polyurethane (FWPU). Our results show that fluorine units are present on the surface of FWPU films. The introduction of FDMA side groups slightly decreases the storage and thermal stability of FWPU but does not affect its usability and significantly increases its hydrophobicity. The result of a repelling test demonstrates that the introduction of FDMA side groups endows the WPU films with excellent waterproofing and antifouling properties. This new method provides a facile and effective way to fabricate of FWPU for its practical application in waterproof and antifouling coatings.