Adsorption and aggregation of a cationic cyanine dye on layered clay minerals

摘要

The adsorption and aggregation of a cationic cyanine dye, l,l'-diethyl-2,2'-cyanine (pseudoiso- cyanine; abbreviated as PIC), on various clays have been investigated. The PIC formed J-aggre- gates on Na-montmorillonite and synthetic Na--tluor-tetrasilicic mica (TSM), while they distributed molecularly on synthetic Na--saponite and synthetic Na-hectorites. The particle size of the clays was considered to be a dominant factor to control the aggregation of PIC. The J-aggregate formation was suppressed when tetramethylammonium--montmorillonite was employed as a host material. Ethylene glycol in the suspension was also responsible for the suppression of J-aggregate formation of PlC. Thus, the aggregation of PlC was effectively controlled by the species surrounding the PIC cations as well as the nature of clays.