Carpenter's Rule Folding in Rigid-Flexible Block Copolymers with Conjugation-Interrupting, Flexible Tethers Between Oligophenylenevinylenes.

Rigid-flexible segmented block copolymers were synthesized and characterized as 4.5-oligophenylenevinylene chromophores tethered by flexible, conjugation-interrupting 1,2-ethanedioxy or 1,4-butanedioxy units. The flexible tethers allow the possibility of collapsed order chromophore assemblies within individual polymers by chain folding at specific sites much like an old fashioned, folding carpenter's rule. Our results indicate that using a short, flexible tether in a rigid-flexible segmented copolymer can result in collapsed rodlike structures as signaled by strongly quenched photoluminescence, even after thermal annealing. Such ability to "program" folding and tertiary structure in conjugated copolymers is important for solid-state organic light emitting materials and understanding of organic chromophore self-assembly.