Upcycling Commodity Polymers into Semiconductors by Sequential Grafting of Aromatic Units through Regioselective Iodination and Living Suzuki–Miyaura Catalyst-Transfer Polymerization

Aromatic commodity polymers possess outstanding thermal and mechanical properties, however, despite recent advances in recycling and functionalization strategies, their reuse remains limited due to the restricted scope of available upcycling approaches. Here we report a sequential postpolymerization strategy that enables precise C-H iodination of aromatic polymers followed by controlled transformation into functional graft copolymers, preserving molecular weight and processability without inducing chain scission or cross-linking. Mild electrophilic iodination using hypervalent iodine reagents affords regioselective and tunable halogenation across a broad range of commodity plastics, including polystyrene, polysulfone, polycarbonate and mixed postconsumer wastes. The resulting iodinated polymers serve as well-defined macroinitiators for living Suzuki-Miyaura catalyst-transfer polymerization, enabling the growth of p- and n-type conjugated polymer from the commodity polymers with controlled grafting density and arm length. This approach preserves the intrinsic performance of the parent polymers while introducing new optoelectronic functionality. Further application to styrene-based elastomers leads to graft-induced microphase separation, yielding stretchable semiconducting materials with enhanced mechanical robustness and strain-resilient charge transport. This work establishes a general platform for functional upcycling of aromatic commodity plastics into advanced materials.