Straightforward Synthesis of Conjugated Block Copolymers by Controlled Suzuki-Miyaura Cross-Coupling Polymerization Combined with ATRP

Catalytic chain growth Suzuki-Miyaura polymerization of an AB-fluorene monomer using isolated (Ini1) or in situ generated (Ini2) Phos-Ph-Pd((Bu3P)-Bu-t)Br as an initiator afforded well-defined heterodifunctional polyfluorenes featuring a phosphonate group (initiating chain end) and a radically polymerizable (Phos-PF8-Sty) or atom transfer radical polymerization (ATRP)-initiating (Phos-PF8-AlkylBr) group (terminating chain end). The resulting Phos-PF8-AlkylBr polymer was directly employed for the growth of a second nonconjugated block by controlled activators regenerated by electron transfer ATRP without the need for further intermediate conversion steps. The PF8 macroinitiator was found to be a viable initiator for the generation of narrowly distributed diblock copolymers with a controlled block length of PF8 and polystyrene, poly(methyl methacrylate), or poly(2-ethylhexyl methacrylate), respectively. Novel conjugated nonconjugated comb polymers were generated by controlled radical copolymerization of PF8 macromonomers, bearing a styrene end group, with styrene or methacrylates. Thereby, it was possible to tune the number of phosphonate moieties per chain between 2 and 15.