INVESTIGATION OF THE MICROPOLARITY OF REVERSE MICELLES USING QUINOLINIUM BETAINE COMPOUNDS AS PROBES

N-octyl-quinolinium betaine is introduced as an absorption probe for t he micropolarity of the interior of reverse micelles. Its solubilizati on by reverse micelles and water/oil microemulsions of Aerosol-OT in i sooctane is compared with that of N-methyl-quinolinium betaine at vari ous water contents of the solution. Analysis of the excitation energie s in the visible range of the spectrum indicates that the methyl deriv ative probes the polarity of the aqueous pool of the micelle, whereas the octyl derivative behaves as a cosurfactant probe that reports on t he polarity of the water/oil interfacial region. (C) 1994 Academic Pre ss, Inc.