Grafting Modification of Poly(vinylidene fluoride‐trifluoroethylene) via Visible‐Light Mediated C–F Bond Activation

Abstract

In this work, a strategy of C-F bond activation for grafting modification of poly(vinylidene fluoride-trifluoroethylene) (h-P(VDF-TrFE), TrFE is dominantly as -CF 2 CH 2 -CFHCF 2 -sequence) using an Ir-based photoredox catalyst is reported. The graft polymerization exhibits first-order kinetics, and the chemical composition of the graft copolymer can be easily adjusted by changing the reaction conditions. Importantly, the side reaction of dehydrofluorination (𝜷-H elimination) can be effectively avoided, which occurs in the previously reported copper complex catalytic system. Moreover, the purification process is greatly simplified due to the extremely low content of catalyst added. This work may provide a facile strategy for incorporating functional groups into h-P(VDF-TrFE) via directly activating C-F bond under mild conditions.

Selective and Controlled Grafting from PVDF-Based Materials by Oxygen-Tolerant Green-Light-Mediated ATRP

“…More DMSO resulted in higher conversions and higher grafting densities and as such may be used to tune the architecture of the grafted copolymers. Polymerizations from PVDF, as a poor initiating system with mechanistically ill-defined process, are plagued by the formation of unattached homopolymers, especially when light-mediated process is used. ,,,, These require laborious and repeated precipitations into selective solvents (e.g., PMMA/PMA-selective chloroform) for quantitative separation.…”

“…Polymerizations from PVDF, as a poor initiating system with mechanistically illdefined process, are plagued by the formation of unattached homopolymers, especially when light-mediated process is used. 23,29,69,71,72 These require laborious and repeated precipitations into selective solvents (e.g., PMMA/PMAselective chloroform) for quantitative separation. Diffusion-ordered NMR spectroscopy (DOSY NMR) was used to confirm the grafting as well as to exclude formation of unattached homopolymers.…”

“…In another report, an expensive iridium-based photoredox complex, fac-[Ir(ppy) 3 ], was used for visible-lightmediated ATRP. 23 A more challenging P(VDF-co-TFE) polymer was used, and the grafting efficiencies were relatively low, i.e., up to 12.2%. Recent reports by Loos et al explored metal-free photomediated ATRP to obtain PVDF-based block copolymers and raised importance of avoiding residual copper in these materials for biomaterials and microelectronics.…”

Tailoring the Dielectric Performance of Poly(vinylidene fluoride-co-tetrafluoroethylene) through Chemical Grafting via Visible-Light Induced C–F Bond Activation

“…Drawing inspiration from organic chemistry, our group facilely grafted various acrylate monomers onto P(VDF-TrFE) using this catalyst, demonstrating the feasibility of activating C−F bonds in PVDF-based fluoropolymers through photoredox catalysis. 27 In this work, the successful regulation of the ferroelectric behavior of P(VDF-TFE) was achieved by grafting poly-(methyl methacrylate) (PMMA) side chains via visible lightinduced C−F bond activation. The chemical structure of the graft copolymer was confirmed by 1 H NMR, and the effect of the grafted PMMA content on the crystallization and dielectric properties of P(VDF-TFE) was systematically studied.…”

“…The mechanism involves a single electron transfer from the photoredox catalyst to the trifluoromethylarene substrate, followed by C–F cleavage and the generation of corresponding radicals that undergo addition reactions with olefins. Drawing inspiration from organic chemistry, our group facilely grafted various acrylate monomers onto P­(VDF-TrFE) using this catalyst, demonstrating the feasibility of activating C–F bonds in PVDF-based fluoropolymers through photoredox catalysis …”