Coil‐helix and sheet‐helix block copolymers via macroinitiation from telechelic ROMP polymers

Coil‐helix and sheet‐helix block copolymers are synthesized by combining the ring‐opening metathesis polymerization (ROMP) of norbornene or paracyclophanediene with the anionic polymerization of phenyl isocyanide. Key to the design is the use of an μ‐ethynyl palladium (II) functionalized chain‐transfer agent (CTA) that can be exploited in a stepwise manner for the termination of ROMP and the initiation of the anionic polymerization. Both the coil‐ and sheet‐macroinitiators, and the ensuing covalent block copolymers, are analyzed using 1H NMR spectroscopy and gel‐permeation chromatography. In all cases, the Pd‐end group is maintained and all polymers demonstrate a monomodal distribution with dispersities (Đ) of 1.1–1.4. The resulting helix‐coil and helix‐sheet block copolymers formed by the macroinitiation route still demonstrate their intrinsic properties (fluorescence, preferential helix‐sense).