Characterization of monomeric and gemini cationic amphiphilic molecules by fluorescence intensity and anisotropy. Part 2

Four fluorophores of different nature, structure and properties were employed as probes for the characterization of a series of alkanediyl-alpha,omega-bis(alkyldimethyl ammonium bromide) surfactants. Pyrene and 3-(2-Benzothiazolyl)-7-(diethylamino)coumarin (coumarin 6) fluorescence intensity as well as coumarin 6 and fluorescein sodium salt fluorescence anisotropy were used to determine cmc whilst coumarin 6, fluorescein sodium salt and perylene fluorescence anisotropy was exploited to provide information on micellar structure; cmc values were confirmed using conductivity measurements. Conductivity data were analysed by means of a method which reveals the formation of ion pairs or premicellar aggregates; this approach was useful to justify and confirm results obtained using fluorescence. (C) 2009 Elsevier Ltd. All rights reserved.