Bruno Ameduri: Deeper Insight into the RAFT Polymerization of Vinylidene Fluoride

Though many studies deal with the controlled radical polymerization (or RDRP) of styrene and acrylate monomers, a few works have been achieved on that of fluorinated monomers. RDRP protocols for vinylidene fluoride (VDF) are still very elusive. In contrast to the MADIX copolymerization of VDF with other comonomers (TFP, PMVE, and MAF),^1-3 that of VDF has been very rarely reported.⁴ The synthesis of PVDF using MADIX solution polymerization was thus investigated in details, as follows: (figure)

More efficient protocols of solution polymerization were developed and afforded relatively well-defined PVDF.^4-5 The careful polymer chain-end monitoring using MALDI-TOF as well as ¹H, ¹⁹F, and HETCOR ¹H-¹⁹F NMR nonetheless revealed that VDF reverse additions and transfer to solvent reactions severely affect the control of the polymerization.^4-6 Indeed, these undesired reactions are responsible for a non-negligible loss of CTA and for the accumulation of non-reactive polymer chains in the reaction medium.⁴

These reactions lead to the synthesis of PVDF with high chain-end functionality, and attempts to reinitiate further chains have been explored to lead to original graft copolymers⁷ and block copolymers.⁸ This work is the first comprehensive study of the MADIX solution polymerization of VDF and further trends on the limits of RAFT are also discussed.⁵