The synthesis and solution properties of hyperbranched polyglycerols modified with hexafluorobutyl acrylate

A series of well-defined fluorinated hyperbranched block copolymers poly(glycerol)-b-poly(hexafluorobutyl acrylate) (PG-b-PHFBA) were prepared by atom transfer radical polymerization (ATRP) of 2,2,3,4,4,4-hexafluorobutyl acrylate (HFBA) in THF, using bromoester-terminated hyperbranched polyglycerol (PG-g-Br) as a macroinitiator. 1H NMR, 13C NMR, 19F NMR, GPC, FT-IR were employed to characterized the molecular structure of PG-b-PHFBA. The surface properties and micellization behavior of the copolymers in ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) was studied by surface tension measurements and dynamic light scattering (DLS). The results showed that the copolymers in ILs could depress surface tension in a manner analogous to aqueous solutions, and the γCMC and critical micelle concentration (CMC) of the multiarm copolymers decreased with the increase of the PHFBA arm length. The DLS results demonstrated that the copolymer formed unimolecular micelles in ILs at the lower concentration, and two kinds of aggregates with Dh 0.7–3 nm and 100–500 nm were detected at higher concentrations.