An Amphiphilic Hemicyanine Dye Employed as a Sensitive Probe of Water in Reverse AOT Micelles

When the amphiphilic hemicyanine dye N - n -heptyl-4-(2-(4-(dimethylamino)phenyl)ethenyl)pyridinium bromide is solubilized in reverse AOT micelles, it forms an adduct which extensively modifies absorption and fluorescence spectra of the dye. The formation of an adduct is very sensitive to the presence of water. Thus the water content of AOT micelles can be accurately monitored by the photophysical behavior of the dye. In particular the red edge excitation shift can be used as a handy and accurate index to determine the water content.