Polymers with novel topologies by ring-opening metathesis polymerization of macromonomers
Résumé
This paper reviews the possibilities of engineering novel macromolecular topologies via ªlivingº ring-opening metathesis polymerization (ROMP) of miscellaneous macromonomers. It is shown that multibranched polystyrene poly(ethylene oxide) and polybutadiene poly-macromonomers of varying compactness and branch number can be prepared by ROMP of corresponding macromonomers, provided the macromonomers carry an end-standing norbornene unsaturation. Janus-type ar-chitectures are also accessible by this technique: such entirely novel topologies can be obtained by sequential ROMP of two different macromonomers whereas their statistical copolymerization affords heteroarmed macro-molecules. Advantage has also been taken of the versatility of this technique to prepare compact polymeric architectures that behave like unimicellar systems: structures whose inner part and outer layer are chemically different can be derived through homopoly-merization of macromonomers that are themselves block copolymers.