Amphiphilic block copolymers of poly(vinylidene fluoride) and poly(ethylene glycol)

Amphiphilic block copolymers of poly(ethylene glycol) (PEG) and poly(vinylidene fluoride) (PVDF) were successfully synthesized by growing poly(vinylidene fluoride) on PEG-chain transfer agent (PEG-macro-CTA) using reversible addition–fragmentation chain transfer (RAFT) polymerization. MeO-PEG-XA, and XA-PEG-XA macro-CTAs (XA refers to the xanthate moiety), synthesized by esterification of MeO-PEG-OH (20,000 g mol⁻¹) and HO-PEG-OH (20,000 g mol⁻¹) with 2-bromopropionyl bromide followed by reaction with potassium ethyl xanthate, were used to synthesize MeO-PEG-b-PVDF and PVDF-b-PEG-b-PVDF, respectively. The synthesized macro-CTAs and block copolymers were characterized by NMR (¹H, ¹³C and ¹⁹F), FTIR, and SEC. Furthermore, the PVDF/PEG block copolymer formation was proved by ¹H DOSY NMR. The thermal properties were determined by TGA and DSC. The crystallinity and electroactive phases were revealed by XRD and FTIR. The size and shape of self-assembled block copolymers in DMF/water mixtures were determined by DLS, TEM and critical micelle concentration with fluorescence spectroscopy. The influence of molecular weight and PVDF content on the properties of copolymers is discussed.