Preparation and properties of 100% renewably sourced poly(trimethylene ether) glycol‐based waterborne polyurethane with perfluoropolyether unit

Abstract A series of fluorinated waterborne polyurethane (FWPU) with different fluorine contents were synthesized via a self‐emulsifying method from 100% renewably sourced poly(trimethylene ether) glycol and perfluoropolyether (PFPE). All the FWPU dispersions exhibited good storage stability with average particle size ranging from 65 to 85 nm. Compared with the neat WPU, the water contact angle of FWPU‐15 film was significantly increased to 100° when the PFPE content was 15 wt%, and the surface tension was reduced to 19.9 mN/m. The hydrophobicity of the FWPU films was further enhanced after being annealed at 140°C for 3 h due to the migration of fluorine‐containing segments to the surface as revealed by x‐ray photoelectron spectroscopy and atomic force microscopy analysis. With the introduction of PFPE in FWPU, the micro‐phase separation between hard and soft segments was increased. Meanwhile, the tensile strength, hardness, and modulus of the films were significantly enhanced. The FWPU films exhibited excellent water resistance (water absorption down to 4.8%) and coating properties. Overall, this work provides a new kind of bio‐based waterborne polyurethane materials with superior hydrophobic properties, which have potential applications in coating fields.