Block Copolymer Synthesis via Chemoselective Stepwise Coupling Reactions

Chemoselective stepwise coupling between living polymers and a heterobifunctional-linking agent is shown to be a powerful methodology for block copolymer synthesis. This synthetic strategy is based on the quantitative formation of end-functionalized precursors in the first coupling step. These end-functionalized precursors were reacted with further living polymers, thereby producing well-defined diblock copolymers, triblock terpolymers and a tetrablock quaterpolymer. The behavior of chloro(chloromethyl)dimethylsilane, chloro(3-chloropropyl)dimethylsilane and (bromomethyl)chlorodimethylsilane against macroanions of different reactivity, prepared through living anionic polymerization, was studied. It is demonstrated that the applicability range of the presented methodology is exceptionally wide, and expands the limits of conventional methods based on sequential monomer addition considerably.