Development of ratiometric probes for microemulsion studies

Water-in-oil reverse-phase microemulsions were studied to determine the effects of changing the concentrations of the components of the microemulsions on the shape, sizes, and interactions of the particles of the microemulsion system. Two fluorescent probes were used in the measurement and analysis of bis(2-ethylhexyl) sulfosuccinate (AOT) water in octane reverse phase microemulsions. Dansylpiperidine and 9-aminoacridine were chosen as the fluorescent probes used in the analysis. The experiment consisted of the analysis in solvents of differing polarity, AOT microemulsion solutions of various water, surfactant, and octane ratios, and four component microemulsions. The four component microemulsions consisted of solutions containing AOT, water, octane and tertiary butyl alcohol. The resulting spectra of the fluorescent probes within the various microemulsion solutions were compared to those of the solvent series to analyze the effects of changing local environment on the fluorescent species and to give a comparison of the polarity of the environment in which the probe was located. The different regions of the microemulsions system had very different polarity characteristics, which were observed and analyzed through the fluorescent signals of the probes within the microemulsion system. The effects on the inner water core of the emulsion, the interface of the surfactant molecules with both solvents, and the outer organic phase (by changing the concentrations of the microemulsion components) were determined and are presented in the following paper