Photophysical and photochemical properties of rhodamine 6G in alcoholic and aqueous sodium dodecylsulphate micellar solutions

Commissariat à l'Energie Atomique — Centre d'Etudes Nucléaire de Saclay, URA 331 CNRS, F-91191 Gif-sur-Yvette Cedex France; R. Bonneau,; J.P. Morand; Photophysique et Photochimie Moléculaire, URA 348 CNRS, Université de Bordeaux I, F-33405 Talence Cedex France
Journal of Photochemistry and Photobiology A: Chemistry 01/1991; DOI: 10.1016/1010-6030(91)80032-D

ABSTRACT The photodecomposition of the rhodamine 6G (R6G) dye dissolved in n-alcohols and aqueous sodium dodecylsulphate (SDS) micellar solution was investigated under continuous UV-visible illumination. The results indicate that in alcohol solution the photodecomposition efficiency increases with the dye concentration. It also depends on the nature of the alcohol the lowest efficiency being observed in ethyleneglycol. The mechanism involves the electron transfer reaction of the triplet excited state with a ground state dye molecule (T + S0 → R+ + R−. In aqueous SDS micellar solution, the R6G cation is embedded in the hydrophobic interior of the micelle close to the negatively charged sulphate end groups. We show that a rather high concentration (3 × 10−3 M) of R6G can be dissolved in 10−1 M SDS aqueous solution, protecting R6G from the electron transfer reaction and secondary decomposition reactions.

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