Synthesis and self-assembly of PMBTFVB-g-PNIPAM fluorine-containing amphiphilic graft copolymer

Two well-defined perfluorocyclobutyl aryl ether-based amphiphilic graft copolymers containing a hydrophobic poly(2-methyl-1,4-bistrifluorovinyloxybenzene) (PMBTFVB) backbone and hydrophilic poly(N-isopropylacrylamide) (PNIPAM) side chains were synthesized via sequential thermal step-growth [2 pi + 2 pi] cycloaddition polymerization of 2-methyl-1,4-bistrifluorovinyloxybenzene and atom transfer radical polymerization (ATRP) of N-isopropylacrylamide (NIPAM). PMBTFVB homopolymer was converted to PMBTFVB-Cl macroinitiator by monochlorination of the pendant methyls with N-chlorosuccinimide and benzoyl peroxide. A grafting-from strategy was then adopted for preparing well-defined PMBTFVB-g-PNIPAM graft copolymers with narrow molecular weight distributions (M-w/M-n < 1.30) via ATRP of NIPAM, which was initiated by the Cl-containing macroinitiator. The critical micelle concentration (cmc) was determined by a fluorescence probe technique and the effects of salinity on the cmc of PMBTFVB-g-PNIPAM graft copolymer were also investigated.