AGGREGATION OF ORGANIC-DYES ON STARBURST DENDRIMERS

The adsorption and aggregation of organic dyes methylene blue, thionin e and thiopyronine on anionic starburst dendrimers (SBD) was studied b y UV-Vis and fluorescence spectroscopy. The aggregation of the dyes de pends strongly on the generation of SBD. For SBDs of later generation the aggregation occurs more readily and the number of dye molecules in volved in one aggregate is larger than for earlier generations. It is proposed that dyes like methylene blue stack perpendicular to the surf ace of the SBDs and not as a pile parallel to the surface. UV-Vis and fluorescence experiments give identical results. In 7addition, the ads orption and aggregation of fluorescein on cationic SBDs was studied, w hich depends strongly on the generation of the SBDs.