Controlled polymerizations as tools for the design of star-like and dendrimer-like polymers
Résumé
This paper highlights our recent efforts to engineer polymer chains in star-like and dendrimer-like architectures using atom-transfer radical polymerization (ATRP) and anionic ring-opening polymerization (AROP) of ethylene oxide as synthetic tools. The scope and limitations of ATRP are first discussed when this method of controlled radical polymerization is applied to multifunctional initiators for the synthesis of star polymers by the core-first approach. The switch from ATRP to AROP of ethylene oxide and vice versa allows access to branched amphiphilic block copolymers exhibiting core-shell structures. Stress is also put on the methodologies for the selective branching of polymeric chain-ends, with a view to introducing omega-geminal functionalities from which further polymer branches can be grown. When linear polymer precursors are used, such a strategy leads to asymmetric and mikto-arm stars but the same can be applied to multi-arm stars so as to generate so-called 'dendrimer-like (co)polymers' that are dendrimers with true macromolecular generations.