Main-chain PPEGMEMA-b-PBTFVPP-b-PPEGMEMA perfluorocyclobutyl aryl ether-based amphiphilic ABA triblock copolymer: synthesis and self-assembly

A series of perfluorocyclobutyl aryl ether-based amphiphilic ABA triblock copolymers consisting of hydrophilic poly[poly(ethylene glycol) methyl ether methacrylate] (PPEGMEMA) and hydrophobic poly(2,2′-bis(4-trifluorovinyl-oxyphenyl)propane) (PBTFVPP) blocks were synthesized via the site transformation strategy. A semi-fluorinated PBTFVPP segment was first prepared via thermal step-growth cycloaddition polymerization of BTFVPP trifluorovinyl aryl ether monomer followed by end functionalization to be transformed into Br-PBTFVBP-Br macroinitiator bearing one ATRP initiating group at each end. The target PPEGMEMA- b -PBTFVPP- b -PPEGMEMA triblock copolymers with relatively narrow molecular weight distributions ( M w / M n ≤ 1.32) were synthesized via ATRP of PEGMEMA macromonomer initiated by Br-PBTFVBP-Br macroinitiator. A fluorescent probe technique was used to determine the critical micelle concentrations (cmc) of the obtained amphiphilic copolymers in aqueous solution. The morphologies of the micelles formed by the copolymers were investigated by transmission electron microscopy. It was shown that such triblock copolymers could self-assemble into ovals, well-defined cylinders, and spheres in aqueous solution with different initial water contents and compositions. A novel perfluorocyclobutyl aryl ether-based amphiphilic ABA triblock copolymers were synthesized via the site transformation strategy using sequential thermal [2π + 2π] step-growth cycloaddition polymerization and ATRP.