Original Vinylidene Fluoride-Containing Acrylic Monomers as Surface Modifiers in Photopolymerized Coatings

Abstract

The syntheses of original acrylic monomers containing vinylidene fluoride (VDF) units, prepared through a four-step process starting from the telomerization of VDF with iodotrifluoromethane, are presented. By modifying the [CF3I]0/[VDF]0 initial molar ratios, different CF3(VDF)nI telomers of various molecular weights were obtained. VDF content and the microstructure of the VDF telomers were determined by 19F NMR spectroscopy, while gas chromatography confirmed the average number of VDF units in each telomer. The radical addition of these telomers onto allylic alcohol led to original oligo(VDF)-containing iodohydrins that were reduced into novel ϖ-hydroxyl-VDF telomers. These latter were acrylated, and the resulting VDF-containing macromonomers were added in low amount (0−1% w/w) into a reference telechelic hydrogenated diacrylic resin and copolymerized through the UV-curing technique. The kinetics of the photopolymerization, monitored by IR spectroscopy, and the bulk properties of the film were independent of the amount of these PVDF additives, but peculiar surface properties were shown. The low concentration of the PVDF macromonomers made the surface of the cured networks both hydrophobic and oleophobic. The surface modification, assessed by contact angles and XPS spectroscopy, concerned one side of the films. The films coated on a polar surface showed on the air side a lower surface tension than that of the substrate side, which kept the same properties as those of the pure hydrogenated resin, including a good adhesion to the substrate.