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Abstract
The fluorescence behavior of pyrene in oil droplets of a surfactant-free oil-in-water emulsion was studied for benzene, fluorobenzene, n-hexane and cyclohexane droplets in water. The excimer-monomer fluorescence ratio immediately after sonication, I^sub E^/I^sub M^(0), of the benzene/water emulsion was 8-10times larger than for the benzene solution. The ratio I^sub E^/I^sub M^(t) increased in the first 10-20min before it decreased to zero. Similar behavior was observed for the fluorobenzene/water emulsion, while I^sub E^/I^sub M^(0) for emulsions with n-hexane and cyclohexane was smaller than for benzene and fluorobenzene/water emulsions. I^sub E^/I^sub M^(t) hardly changed with time for the n-hexane and cyclohexane/water emulsions. This different behavior was attributed to the increased solubility of nanometer-size droplets with benzene and fluorobenzene.[PUBLICATION ABSTRACT]