Poly(fluoroacrylate)s with tunable surface hydrophobicity via radical copolymerization of 2,2,2-trifluoroethyl α-fluoroacrylate and 2-(trifluoromethyl)acrylic acid

Bruno Ameduri (1) , Vincent Ladmiral (1) , Sanjib Banerjee (1) , Bhausaheb Tawade (1) , Lionel Xavier Dupuy (2) , Michael Macdonald (3)

1 ICGM - Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier
2 The James Hutton Institute
3 Electronic Engineering and Physics Division, University of Dundee, Dundee, DD1 4HN, United Kingdom

The synthesis of poly(fluoroacrylate)s with tunable wettability and improved adhesion for potential application as functional coatings was achieved via radical copolymerization of 2,2,2-trifluoroethyl α-fluoroacrylate (FATRIFE) with 2-(trifluoromethyl)acrylic acid (MAF), an adhesion-promoting monomer. These copolymerizations, initiated by tert-butyl peroxypivalate at varying comonomer feed ([FATRIFE]0/ [MAF]0) ratios led to a series of poly(FATRIFE-co-MAF) copolymers with different molar compositions in fair to good conversions (32–87%) depending on the MAF feed content. The microstructures of the synthesized poly(FATRIFE-co-MAF) copolymers were determined by 19F NMR spectroscopy. Even at MAF feed contents higher than 50%, MAF incorporation into the copolymers was lower than 50%, since MAF does not undergo any homopolymerization under radical polymerization conditions. The reactivity ratios of the (FATRIFE; MAF) monomer pair were also determined (rFATRIFE = 1.65 ± 0.07 and rMAF = 0 at 56 °C) evidencing the formation of statistical copolymers. Initiation involving a highly branched perfluorinated radical that released a •CF3 radical enabled the demonstration of the regioselective attack of the latter radical onto the CH2 of FATRIFE. The resulting poly(FATRIFE-co-MAF) copolymers exhibited various glass transition temperatures (Tgs) depending on their compositions. Tg values increased with increasing MAF contents in the copolymer. In addition, their thermal stability (the temperature for 10% weight loss in air, Td10%) increased with increasing FATRIFE content in the copolymer and reached 348 °C (for that containing 93 mol% FATRIFE). Finally, a high copolymer MAF content led to both a good adhesion onto metal substrates and to improved hydrophilicity, as revealed by the decrease of the water contact angle from 107° (for a reference PFATRIFE homopolymer) to 81° (for a copolymer containing 42 mol% MAF).

Mots clés: Poly(fluoroacrylate); radical copolymerization; fluoropolymers; surface properties; NMR

Domaines: Polymères

Bruno Ameduri, Vincent Ladmiral, Sanjib Banerjee, Bhausaheb Tawade, Lionel Xavier Dupuy, et al.. Poly(fluoroacrylate)s with tunable surface hydrophobicity via radical copolymerization of 2,2,2-trifluoroethyl α-fluoroacrylate and 2-(trifluoromethyl)acrylic acid. Polymer Chemistry, 2017, 8, pp.1978-1988. ⟨10.1039/c7py00209b⟩. ⟨hal-01493809⟩