“One pot” synthesis of fluorinated block copolymers using a surface-active ATRP initiator under emulsion polymerization conditions

Abstract

Three fluorinated block copolymers have been prepared successfully in emulsion system using a surface-active atom transfer radical polymerization (ATRP) initiator disodium 4-(10-(2-bromo-2-methylpropanoyloxy)decyloxy)-4-oxo-2-sulfonatobutanoate (1). The copolymerization can be conducted in “one pot” under activator generated by electron transfer (AGET) ATRP in emulsion conditions, thus greatly simplifying the operations and workup. The anionic surface-active ATRP initiator (1) and nonionic surfactant OP-10 may form synergistic stabilizers that effectively guarantee stability of the final latex. The ATRP follows first-order kinetics and has living/controlled characteristics based on the researching results of polymerization of trifluoroethyl methacrylate (TFEMA). Surface studies indicate that the fluorinated block copolymers reveal lower surface energy and stronger hydrophobic property compared with those non-fluorinated polymers. The decreasing order of surface energy of the polymers is: polystyrene (PS) > polytrifluoroethyl methacrylate-block-polystyrene (PTFEMA-b-PS) > polyhexafluorobutyl methacrylate-block-polystyrene (PHFBMA-b-PS) > polydodecafluoroheptyl methacrylate-block-polystyrene (PDFHMA-b-PS) > polydodecafluoroheptyl methacrylate (PDFHMA). Fluorinated homopolymer PDFHMA and copolymer PDFHMA-b-PS exhibits relatively low-surface energy, which is ascribed to the long and flexible DFHMA units containing in the polymers.