POLYMERS WITH NOVEL TOPOLOGIES BY RING-OPENING METATHESIS POLYMERIZATION OF MACROMONOMERS

This paper reviews the possibilities of engineering novel macromolecul ar topologies via ''living'' ring-opening metathesis polymerization (R OMP) of miscellaneous macromonomers. It is shown that multibranched po lystyrene poly(ethylene oxide) and polybutadiene polymacromonomers of varying compactness and branch number can be prepared by ROMP of corre sponding macromonomers, provided the macromonomers carry an end-standi ng norbornene unsaturation. Janus-type architectures are also accessib le by this technique: such entirely novel topologies can be obtained b y sequential ROMP of two different macromonomers whereas their statist ical copolymerization affords heteroarmed macromolecules. Advantage ha s also been taken of the versatility of this technique to prepare comp act polymeric architectures that behave like unimicellar systems: stru ctures whose inner part and outer layer are chemically different can b e derived through homopolymerization of macromonomers that are themsel ves block copolymers. (C) 1998 John Wiley & Sons, Ltd.