Solvent-free fabrication of tough self-crosslinkable short-fluorinated copolymer nanocoatings for ultradurable superhydrophobic fabrics

As long-perfluorinated side chain polymers are phasing out due to healthy and environmental concerns, short-fluorinated polymers are garnering increasing attention as a substitute for superhydrophobic coatings. Challenges, however, are to be addressed due to the poor dynamic water repellency and unsatisfactory durability of short-fluorinated polymer coatings. This work reports the fabrication of self-crosslinkable poly(perfluorohexylethyl acrylate-co-isocyanato ethyl methacrylate) nanocoating with good dynamic water repellency and high mechanical strength using a solvent-free initiated chemical vapor deposition (iCVD) method. The employment of highly reactive isocyanate groups in the coating not only facilitated covalent binding with functional groups on the substrate surface, but also enabled self-crosslinking reactions in the presence of water vapor. Crosslinking immobilized the fluorinated chains on the surface, thus alleviating the contact angle hysteresis. The crosslinked network also significantly improved the mechanical strength of the coating. Without affecting fabric morphology, the coating enabled superhydrophobicity of different fabrics with water sliding angle as low as 3˚. Such superhydrophobicity was well maintained after various harsh durability tests, including sandpaper abrasion for up to 20,000 cm, ultrasonication and boiling for more than 12 h, etc. The achieved durability was attributed to the enhanced adhesion strength and excellent mechanical property of the coating. This work thus paves a novel way towards eco-friendly fabrication of durable superhydrophobic fabrics.