Synthesis of polyisobutylene-based block copolymers with precisely controlled architecture by living cationic polymerization

During the last two decades we have witnessed the discovery and development of living cationic polymerization. As a result of persistent growth in this field, today living cationic polymerization is an equal counterpart of anionic living polymerization although the latter has a considerably longer history. Living cationic polymerization is an indispensable tool for the preparation of a wide variety of homo-, block-, graft- and functional polymers. This chapter reviews recent efforts in cationic macromolecular engineering with emphasis on fundamental concepts and advanced technologies for polyisobutylene block copolymer synthesis. For block copolymer synthesis by the simple sequential monomer addition technique rationalization is given for the selection of polymerization conditions and monomer addition order. The application of non-(homo)polymerizable monomers such as 1,1-diarylethylenes and furan analogues, coupled with changes in the synthetic approaches for various block copolymer architectures, is described in terms of three categories; capping, coupling, and living coupling reactions. These appear to be versatile synthetic tools for numerous linear di- and triblock copolymers, and block copolymers with non-linear architectures. Finally, current developments in the combination of different polymerization mechanisms are illustrated.