All-cis poly(p-phenylene vinylene)s with high molar masses and fast photoisomerization rates obtained through stereoretentive ring-opening metathesis polymerization of [2,2]paracyclophane dienes with various aryl substituents

Poly(p-phenylene vinylene)s (PPVs) are some of the most widely studied conjugated polymers in academia and industry, but most production methods lack precise control over molar masses and alkene stereochemistry. These critical parameters have a large influence on processability, polymer morphology, and optical properties. Herein, we report the stereoretentive ring-opening metathesis polymerization (ROMP) of [2.2]paracyclophane dienes bearing either a linear alkyl substituent or a branched alkoxy substituent to form all-cis PPVs with great solubility in organic solvents. The introduction of 2-ethylhexyloxy side-chains permits the preparation of PPV with uncharacteristically high molar masses (up to 108.8 kg/mol) for a polymerization with living characteristics. Exposure to UV light (365 nm) rapidly induces isomerization of all-cis alkenes leading to the formation of all-trans PPV. This study proposes an attractive strategy to synthesize soluble all-cis and all-trans PPVs with tunable, high molar masses through careful design of the ROMP monomer.