Use of original ω-perfluorinated dithioesters for the synthesis of well-controlled polymers by reversible addition-fragmentation chain transfer (RAFT)

Abstract

A series of five fluorinated dithioesters PhC(S)SRCH2CnF2n+1 (where R represents an activating spacer and n = 6 or 8) was obtained in fair to high yields (57-88%). These transfer agents were successfully used in reversible addition-fragmentation transfer (RAFT) of styrene (S), methyl methacrylate (MMA), ethyl acrylate (EA) and 1,3-butadiene. Well-chosen fluorinated dithioesters were able to lead to a good control of the radical polymerization of these monomers (i.e., molar masses of the produced polymers increased linearly with the monomer conversion and the polydispersity indexes ranging between 1.1 and 1.6 remained low). The relationship between the structures of the dithioesters and the living behavior of the radical polymerization of these above monomers is discussed and it is shown that the nature of the R group influences the living behavior from different contributions to radical stabilization. Furthermore, the RAFT process also yielded PMMA-b-PS and PEA-b-PS block copolymers bearing a fluorinated moiety.