Interaction between dyes and polyelectrolytes. X. Excitation energy transfer in cationic dye–polyanion system

The quantum yield for the trypaflavine-photosensitized oxidation of 1-(methylthio)ethyl-3-carbamoylpyridinium chloride to 1-(methylsulfinyl)ethyl-3-carbamoylpyridinium chloride increased with increase in the concentration of methylene blue added. It was inferred that the increase in the quantum yield is due to the excitation energy transfer from trypaflavine to methylene blue. The efficiency of excitation energy transfer was enhanced on addition of potassium poly(vinyl sulfate) and was dependent on the polyanion/dye ratio. The efficiency of excitation energy transfer at the most appropriate polyanion/dye ratio was about 5 times as high than that in the absence of polyanion. The binding of dye to potassium poly(vinyl sulfate) was investigated spectrophotometrically. Correlation with the dye binding to potassium poly(vinyl sulfate) and the efficiency of excitation energy transfer between dyes was discussed.