Applications of Anionic Polymerization to Macromolecular Engineering

The development of “macromolecular engineering” owes much to living anionic polymerizations. When carried out under conditions preventing spontaneous transfer and termination reactions, and with efficient initiators, these processes are well suited to the synthesis of model macromolecules of various kinds. Functionalizations at chain end can be achieved upon induced deactivation; macromonomer synthesis, end-to-end cyclization, and chain extension processes can be achieved; and end-linking reactions yield model networks. The use of anionic polymerization processes to synthesize well-defined block copolymers exhibiting low heterogeneity in molecular weight and in composition is of major importance because of the various specific applications of such materials. New efficient bi- and multifunctional metal-organic initiators have been developed. Recently, progress in star polymer synthesis, including core-first methods, has been achieved. Amphiphilic star-block copolymers have been made, as well as heterostar copolymers, whose cores carry two different kinds of arms (of different chemical natures) in roughly equal numbers. All these novel species have attracted wide interest because of their controlled structure and potential applications.