General and Facile Approach to Exact Graft Copolymers by Iterative Methodology Using Living Anionic In-Chain-Functionalized AB Diblock Copolymers as Key Building Blocks

Abstract

A variety of exact graft copolymers, such as poly(tert-butyl methacrylate)-exact graft-polystyrene (PS), poly(ferrocenylmethyl methacrylate)-exact graft-PS, and poly(2-vinylpyridine)-exact graft-PS, have been successfully synthesized by developing a novel stepwise iterative methodology based on a new concept utilizing living in-chain-(3-tert-butyldimethylsilyloxymethylphenyl) (SiOMP)-functionalized AB diblock copolymers as key building blocks. The methodology basically involves three reaction steps in each iterative process, i.e., (1) living anionic block copolymerization to prepare a living in-chain-SiOMP-functionalized AB diblock copolymer, (2) a transformation reaction of the SiOMP group into an α-phenyl acrylate (PA) function, and (3) a 1:1-addition reaction of the resulting in-chain-PA-functionalized AB diblock copolymer with a living in-chain-SiOMP-functionalized AB diblock copolymer separately prepared to link the two block copolymer chains. By performing the same iterative process involving steps 1–3 several times, the above-mentioned exact graft copolymers having three to five PS branches were synthesized. The resulting polymers were all well-defined in architecture and precisely controlled in chain structure.