Interaction between dyes and polyelectrolytes. XII. Excitation energy transfer between bound dyes

Methylene blue‐photosensitized isomerization of cis‐p‐(phenylazo) phenyltrimethylammonium iodide to the transisomer was used advantageously to investigate the effect of polyanions on the triplet excitation energy trasfer between cationic dyes in aqueous media. The efficiency of the excitation energy transfer was improved by the addition of potassium poly(vinyl sulfate) (PVS), potassium poly(styrene‐sulfonate) (PSS), sodium poly(acrylate) (PAA), and sodium poly(methacrylate) (PMA) and was dependent on the polyanion concentration in the system. PVS and PSS were much more effective than PAA and PMA. The efficiency of the excitation energy transfer under the most appropriate conditions was about 67 times higher than in the absence of polyanions. Correlation with dye binding to polyanions and the efficiency of the excitation energy transfer between dyes was discussed.