J Aggregation of Thiacarbocyanine in Aqueous Gelatin Solutions

The aggregation processes of 3,3′-disulfopropyl-4,4′,5,5′-dibenzo-9-ethylthiacarbocyanine betaine were studied in aqueous gelatin solutions. Gelatin molecules were shown to favor the formation of J aggregates from dye dimers according to the block mechanism. Acidic gelatins much stronger favor J aggregation of the dye than alkaline and, especially, modified gelatins. High contents of microgels and high-molecular-mass fractions in gelatin retard the formation of long-wavelength aggregates.