Influence of Pendant Fluoroalkyl Segments on Properties of Fluoroethylene and Vinyl Ether Polymers and Their Hydrophobic Coatings

Abstract

Hydrophobic coatings that repel corrosive media are more conducive to protecting metals from corrosion. Fluorocarbon resins with a low surface energy are the most ideal materials for preparing hydrophobic surfaces. In this paper, dodecafluoroheptyl methacrylate (DFMA) with rich −CF3 group was introduced into the copolymer of chlorotrifluoroethylene (CTFE) and isobutyl vinyl ether (IBVE) to prepare a series of fluoroethylene and vinyl ether (FEVE) polymers. The high fluorine content of 33.87–43.68 wt % was obtained for FEVE polymers due to the instruction of DFMA containing many fluorine atoms in the side chain. Subsequently, an ethylene glycol monoallyl ether (EGMAE) monomer was introduced for cross-linking with isocyanate. Then, the FEVE polymers were made into varnish coatings. The influence of pendant fluoroalkyl segments of the polymers on the wettability, mechanical properties, and acid and alkali resistance of the coatings was evaluated. The results indicated that the water contact angle (WCA) of the varnish coatings can reach 104.5° and the surface energy of coating decreased to 17.05 mN·m–1 by introducing 0.5 mol of DFMA monomer in the CTFE-IBVE system. Its cross-linked coating can withstand acidic and alkali liquids for up to 30 days, showing excellent chemical stability. In addition, the cross-linked FEVE coatings can reach superhydrophobicity (WCA = 151.5 ± 0.5°, SA = 8 ± 0.8°) by adding only 18 wt % unmodified nano SiO2.