title: Analysis of phase diagram and microstructural transitions in an ethyl oleate/water/Tween 80/Span 20 microemulsion system using high-resolution ultrasonic spectroscopy.
abstract: High-resolution ultrasonic spectroscopy was applied to analyse a pseudo-ternary phase diagram for a mixture consisting of water/ethyl oleate/Tween 80 and Span 20 at 25 degrees C. The measured changes in the ultrasonic velocity and attenuation with concentration of water in oil/surfactants mixtures showed several, well defined stages and transitions between them, which allowed construction of an 'ultrasonic' phase diagram. Quantitative analysis of the ultrasonic parameters enabled characterisation of various phases (microemulsion, liquid crystals and pseudo-bicontinuous) as well as evaluation of the state of the water and particle size in microemulsion phase.
authors.affiliation: School of Chemistry and Chemical Biology University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: Sinead
authors.initials: S
authors.lastname: Hickey
authors.forename: Sue A
authors.initials: SA
authors.lastname: Hagan
authors.forename: Evgeny
authors.initials: E
authors.lastname: Kudryashov
authors.forename: Vitaly
authors.initials: V
authors.lastname: Buckin
mesh_terms: D002626:Chemistry, Pharmaceutical / Q000379:methods; D004655:Emulsions; D006601:Hexoses / Q000737:chemistry; D009829:Oleic Acids / Q000737:chemistry; D010316:Particle Size; D044367:Phase Transition; D011136:Polysorbates / Q000737:chemistry; D013057:Spectrum Analysis / Q000379:methods*; D013501:Surface-Active Agents / Q000737:chemistry; D014465:Ultrasonics; D014867:Water / Q000737:chemistry
chemical_list: D004655:Emulsions; D006601:Hexoses; D009829:Oleic Acids; D011136:Polysorbates; D013501:Surface-Active Agents; D014867:Water; C014822:sorbitan monolaurate; C033180:ethyl oleate