Ž . Applied Clay Science 16 2000 161–170 www.elsevier.nlrlocaterapclaysci Adsorption and aggregation of a cationic cyanine dye on layered clay minerals Nobuyoshi Miyamoto a , Ryo Kawai a , Kazuyuki Kuroda a,b , Makoto Ogawa c,d, ) a Department of Applied Chemistry, Waseda UniÕersity, Ohkubo-3-4-1, Shinjuku-ku, Tokyo 169-8555, Japan b Kagami Memorial Laboratory for Materials Science and Technology, Waseda UniÕersity, Nishiwaseda 2-8-26, Shinjuku-ku, Tokyo 169-0051, Japan c PRESTO, Japan Science and Technology, Japan d Department of Earth Sciences, Waseda UniÕersity, Nishiwaseda 1-6-1, Shinjuku-ku, Tokyo 169-8050, Japan Received 5 October 1998; received in revised form 4 June 1999; accepted 30 August 1999 Abstract X X Ž The adsorption and aggregation of a cationic cyanine dye, 1,1 -diethyl-2,2 -cyanine pseudoiso- . cyanine; abbreviated as PIC , on various clays have been investigated. The PIC formed J-aggre- Ž . gates on Na-montmorillonite and synthetic Na-fluor-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 PIC. Thus, the aggregation of PIC was effectively controlled by the species surrounding the PIC cations as well as the nature of clays. q 2000 Elsevier Science B.V. All rights reserved. Keywords: clay minerals; cyanine dye; J-aggregate; tetramethylammonium; ethylene glycol ) Corresponding author. Department of Earth Sciences, Waseda University, Nishiwaseda 1-6-1, Shinjuku-ku, Tokyo 169-8050, Japan. Tel.: q 81-3-5286-1511; Fax: q 81-3-3207-4950; E-mail: makoto@mn.waseda.ac.jp 0169-1317r00r$ - see front matter q 2000 Elsevier Science B.V. All rights reserved. Ž . PII: S0169-1317 99 00051-4