Temperature-controlled sequence engineering of polar cyclic olefin copolymers

Sequence regulation in polymeric materials plays a critical role in tailoring their macroscopic properties, yet achieving precise sequence control in polar cyclic olefin copolymers (COCs) remains a significant challenge. In this study, we report a temperature-programmed Pd-catalyzed terpolymerization of norbornene (NB), butyl-norbornene (BuNB), and methyl vinyl ketone (MVK), enabling the formation of distinct copolymer sequences from a single monomer feed. By modulating polymerization temperature, we access either gradient-type (NBM5-G) or gradient-block-like (NBM5-GB) architectures, reflecting a shift in monomer incorporation kinetics. These sequence modulation translates into markedly different thermomechanical and optical properties: NBM5-G exhibits superior transparency and flexibility, whereas NBM5-GB displays higher stiffness and reduced transparency due to increased polar-polar interactions. Our findings establish temperature-directed sequence programming as an effective tool for tailoring functional COCs, opening avenues for advanced applications in flexible optics and electronics.