Synthesis of sequence-determined bottlebrush polymers based on sequence determination in living anionic copolymerization of styrene and dimethyl(4-(1-phenylvinyl)phenyl)silane

Abstract

Sequence-determined bottlebrush polymers in which the branches are distributed with determined sequential arrangements are precisely, efficiently and conveniently synthesized. Living anionic polymerization and hydrosilylation were used to synthesize the backbones, branches and bottlebrushes. Sequence-determined backbones, which include perfectly alternating and gradient structures, were obtained by controlling the monomer feed ratios during the living anionic copolymerization of styrene and dimethyl(4-(1-phenylvinyl)phenyl)silane (DPE-SiH). In addition, the sequential arrangements of branch points in gradient copolymers, i.e., SiH groups, were precisely determined using the timing-sample method under high-vacuum conditions. Then, the branches were conveniently grafted onto the backbones with a corresponding distribution of SiH groups via efficient hydrosilylation. The overall efficiency of the coupling reaction was greater than 91%. The solution properties of the synthesized bottlebrush polymers were investigated, and the results indicated that the sequence of branches may exert an influence on the branching factor (g′) and the hydrodynamic radius (R_h).