Brush Polymers Containing Semiconducting Polyene Backbones: Graft-Through Synthesis via Cyclopolymerization and Conformational Analysis on the Coil-to-Rod Transition

Using a grafting-through strategy, brush polymers containing semiconducting polyene backbones were efficiently synthesized by cyclopolymerization for the first time. Macromonomers containing poly(L-lactide) and poly(epsilon-caprolactone), prepared by living ring-opening polymerization, were polymerized using the Grubbs-Hoveyda catalyst to produce high molecular weight (>0.5 M Da) brush polymers. The brush polymers underwent a unique coil-to-rod transition during the aging of the polymer solution, and this conformational change was supported by UV-vis and size-exclusion chromatography (SEC)-viscometry analysis. In addition, the extended conformation of single chains of the brush polymers could be visualized by atomic force microscopy.