Wann‐Yin Lin, Jen‐How Huang, J. Hsu
Aug 30, 1997
Citations
0
Influential Citations
3
Citations
Journal
Journal of Photochemistry and Photobiology A-chemistry
Abstract
Abstract Room temperature phosphorescence (RTP) of 2-bromonaphthalene (2-BN) in SDS micelles has been studied in the presence of variousv salt and surfactant concentrations and at various temperatures. RTP of 2-BN was easily observed in the rodlike micelles of SDS when the added sodium chloride exceeded a certain concentration. The phosphorescence intensity was found to increase sharply during the sphere-to-rod transition because of the tremendous increase in microviscosity. The intensity declined slightly at very high salt concentration, owing to the formation of flexible rods. At a given salt and surfactant concentration, the phosphorescence intensity decreased drastically with increasing temperature, probably because of the decreased aggregation number and microviscosity of the micelles. Moreover, a smaller value of the second cmc and a sharper sphere-to-rod transition were observed at higher temperatures. At a given salt concentration (above the second cmc) and temperature, the phosphorescence intensity increased steadily with increasing surfactant concentration and leveled off above a certain concentration of SDS. This study proposed a potential use of rodlike micelles as a convenient means of observing the RTP of luminophores with an intrinsic heavy atom. On the other hand, RTP of heavy-atom-containing luminophores may also be used as an alternative probe for detection of the sphere-to-rod transition of micelles.