Facile Synthesis of Poly(phenyleneethynylene)-block-Polyisocyanide Copolymers via Two Mechanistically Distinct, Sequential Living Polymerizations Using a Single Catalyst

Facile synthesis of hybrid block copolymers containing two segments that cannot be synthesized under the same polymerization mechanism still remains a great challenge in the field of polymer synthesis. Here we report on one-pot synthesis of hybrid block copolymers containing conjugated poly(phenyleneethylene) (PPE) and stereoregular poly(phenyl isocyanide) (PPI) using palladium(II) complex as a single catalyst. Although the two blocks were polymerized via distinct polymerization mechanism, the block copolymerization were revealed to proceed in a living/controlled chain-growth manner, afforded PPE-b-PPI block copolymers in high yields with controlled molecular weights, narrow molecular weight distributions, and tunable compositions. By using this synthetic method, amphiphilic PPE-b-PPI block copolymers containing hydrophobic PPE and hydrophilic PPI segments were facilely prepared. Such block copolymer can self-assembly into well-defined supramolecular structure in selective solvents. In addition, the one-pot block copolymerization method can be applied to the preparation of other hybrid block copolymers such as PPE-b-poly(1-isocyanohexadecane) (PPE-b-PIH) and PPE-b-poly(quinoxaline-2,3-diyl) (PPE-b-PQD) under living/controlled chain-growth manners.