Star polymers with alternating arms from miktofunctional μ-initiators using consecutive atom transfer radical polymerization and ring-opening polymerization

The synthesis of unique miktofunctional μ-initiators, combining initiator sites for both controlled ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP) arranged in an alternating fashion, is described. This initiator was used to prepare miktoarm star block copolymers in a core-out approach utilizing consecutive ATRP and ROP processes. NMR and GPC studies on the block copolymers comprising poly(methyl methacrylate) (PMMA) and poly(caprolactone) (PCL) confirm the versatility of this approach which is independent of the order of polymerization. Furthermore, amphiphilic alternating arm block copolymers containing poly(caprolactone) and poly(acrylic acid) blocks were also prepared by this method.