A Facile and Highly Efficient Route to Amphiphilic Star-Like Rod-Coil Block Copolymer via a Combination of Atom Transfer Radical Polymerization with Thiol–Ene Click Chemistry

With a combination of atom transfer radical polymerization (ATRP), quasi-living Grignard metathesis method, and thiol–ene click reaction, an amphiphilic star-like rod-coil diblock copolymer poly(acrylic acid)-block-poly(3-hexylthiophene) comprising 21-arm inner coil-like PAA blocks and outer rod-like conjugated polymer poly(3-hexylthiophene) (P3HT) blocks with well-defined molecular structures and narrow molecular weight distribution is synthesized. First, the bromide end-groups of 21-arm star-like ATRP coil polymers PtBA-Br are converted successfully into reactive thioacetate end groups by post-functionalization using potassium thioacetate. Subsequently, 21-arm star-like coil polymers PtBA-SCOCH₃ react with rod-like vinyl-functionalized P3HT to yield functional star-like rod-coil diblock copolymers PtBA-b-P3HT via thiol–ene click reaction, followed by selective hydrolysis of inner PtBA block into PAA block. The present synthetic approach enables the construction of well-defined star-like conformation with few structural limitations in a facile and highly efficient manner due to the robust and orthogonal nature of the thiol–ene click reaction. It may be extended to produce block copolymers with other topologies, such as cylindrical, hyperbranched, and dendritic structures.