Characterization of Multifunctional Reverse Micelles' Interfaces Using Hemicyanines as Molecular Probes. I. Effect of the Hemicyanines' Structure

In this work, we report the behavior of two different hemicyanines, trans-4-[4-(dimethylamino)styryl]-N-methylpyridinium iodide (HC) and 4-[4-(dihexadecylamino)styryl]-N-methylpyridinium iodide (DIA), in water/ sodium 1,4-bis-2-ethylhexylsulfosuccinate (AOT)/benzene reverse micelles media using absorption and emission spectroscopy in addition to the steady-state and time-resolved fluorescence emission techniques. Our results show that the AOT reverse micelles interface has the nontrivial deaggregation property, a result that may have potential application for the preparation of dye lasers, which require a noninteracting monomeric form of the dye. Also, we show that the water interacts with a different region of the AOT moiety depending on the external organic solvent used and, in addition, we also present a nice, simple, and noteworthy method that helps to examine the presence or the absence of organized media. In conclusion, our results show that HC and DIA are powerful dyes to characterize simultaneously different interfaces' properties as they can be used to sense, at the same time, fluidity and specific interactions at the interface. These results are important because those properties are the key for molecular recognition.