Preparation of J-aggregates of Cyanine Dyes in Polymer Films

Abstract

Polymer films containing quinocyanine dyes (1, 1'-diethyl-2, 2'-cyanine chloride and 5, 6, 5', 6'-dibenzo-1, 1'-diethyl-2, 2'-cyanine chloride) were fabricated by dropping aqueous solutions of the cyanine dye and the water- soluble polymer, i. e., high molecular weight carboxylic acid and polyvinylalcohol, on the quartz plate and drying. The aggregation state of cyanine dyes (monomer, dimer, J- aggregate etc.) could be controlled by changing the kind of polymers as well as the ratio of the amounts of dye to the polymer. When sodium alginate, a typical polysaccharide, was used, the J-aggregate of cyanine dyes was formed fairly easily. In case of polymethacrylic acid, the dye molecules were incorporated into the film as monomer or dimer. The J-aggregation seems to be influenced by the kind and the amount of polymer, as well as the electrostatic interaction between cationic dye and anionic polymer. Moreover, we examined the preparation of the polymer film containing two kinds of J-aggregate.