Pyrene fluorescence measurements of metastable oil droplets in surfactant-free oil-in-water emulsions

• Published in: Colloid and polymer science Vol. 280; no. 2; pp. 99 - 106
• Main Authors: SAKAI, T, KAMOGAWA, K, KWON, K. O, SAKAI, H, ABE, M
• Format: Journal Article
• Language: English
• Published: Berlin Springer 01.02.2002; Springer Nature B.V
• Subjects: Benzene; Chemistry; Colloidal state and disperse state; Colloids; Cyclohexane; Droplets; Emulsions; Emulsions. Microemulsions. Foams; Exact sciences and technology; Fluorescence; General and physical chemistry; Hydrocarbons; Pyrenes; Solubility; Surfactants; Water; Molecular diffusion; Hydrocarbon; Oil water emulsion; Fluorescence; Fluorocarbon; Cycloalkane; Droplet; Pyrene; Ostwald ripening; Benzene; Alkane; Cyclohexane; Hexane
• ISSN: 0303-402X; 1435-1536
• DOI: 10.1007/s003960100544

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]