Regulation of Aggregation and Morphology of Cyanine Dyes on Monolayers via Gemini Amphiphiles
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- 作者：Guocheng Zhang ; Xiaodong Zhai ; Minghua Liu ; Yalin Tang ; Yazhou Zhang
- 刊名：Journal of Physical Chemistry B
- 出版年：2007
- 出版时间：August 9, 2007
- 年：2007
- 卷：111
- 期：31
- 页码：9301 - 9308
- 全文大小：1226K
- 年卷期：v.111,no.31(August 9, 2007)
- ISSN：1520-5207
文摘
The aggregation of dyes is of considerable importance in relating to their functions and applications. In thispaper, we have investigated the regulation on the aggregation and morphology of two cyanine dyes, 3,3'-disulfopropyl-4,5,4',5'-dibenzo-9-methylthiacarbocyanine triethylammonium salt (MTC) and 3,3'-disulfopropyl-4,5,4',5'-dibenzo-9-phenylthiacarbocyanine triethylammonium salt (PTC), using a series of gemini amphiphiles(bis(2'-heptadecyl-3'-ethylimidazolium)-1,n-alkane dibromide, abbreviated as Gn, n = 2, 4, 6, 8, 10). It hasbeen found that both of the dyes could be adsorbed onto the monolayers of the gemini amphiphiles throughthe electrostatic and 
- interaction and stacked into H- or J-aggregate. The spacer of the gemini amphiphileshowed good control over the aggregation of MTC: H-aggregate was favored when gemini amphiphiles withshort spacer were applied, while J-aggregation was preferred in the case of longer spacer. Only J-aggregatewas observed for PTC on gemini monolayer, regardless of the structure of the gemini amphiphiles. Interestingmorphologies were observed for all the gemini/dye complex monolayers. Network structure and nanofiberswere formed for the gemini/MTC films transferred below the plateau surface pressure and close to the collapsepressure, respectively. The ability of the complex monolayers to form nanofibers strongly depended on thecomponent amphiphiles, G2 > G4 > G6, and no nanofibers were observed for G8/MTC and G10/MTC afterthe collapse. Only squared domains were observed for gemini/PTC monolayers. When both G2 and G10were mixed, an individual control of the gemini amphiphiles over the aggregation of MTC in the complexmonolayers was observed. The relationship among the spacer, dye structure, and aggregation was revealed.
- interaction and stacked into H- or J-aggregate. The spacer of the gemini amphiphileshowed good control over the aggregation of MTC: H-aggregate was favored when gemini amphiphiles withshort spacer were applied, while J-aggregation was preferred in the case of longer spacer. Only J-aggregatewas observed for PTC on gemini monolayer, regardless of the structure of the gemini amphiphiles. Interestingmorphologies were observed for all the gemini/dye complex monolayers. Network structure and nanofiberswere formed for the gemini/MTC films transferred below the plateau surface pressure and close to the collapsepressure, respectively. The ability of the complex monolayers to form nanofibers strongly depended on thecomponent amphiphiles, G2 > G4 > G6, and no nanofibers were observed for G8/MTC and G10/MTC afterthe collapse. Only squared domains were observed for gemini/PTC monolayers. When both G2 and G10were mixed, an individual control of the gemini amphiphiles over the aggregation of MTC in the complexmonolayers was observed. The relationship among the spacer, dye structure, and aggregation was revealed.