The kinetic evolution of concentrated double emulsions stabilized with small molecule surfactants

摘要

Double emulsions belong to multiple emulsions category. Direct double emulsions (W/O/W) are obtained by dispersing a reverse emulsion (W/O), prepared in the presence of a lipophile surfactant, in an aqueous medium, by using a hydrophile surfactant. In the experiments performed the kinetic evolution of Span 80/SDS (lipophile surfactant/hidrophile surfactant) - type concentrated double emulsions was traced by using a NaCl solution as internal aqueous phase and a glucose solution, isolone to the saline one, as external aqueous phase, while the oily phase was dodecane. Reverse emulsion corpuscles were concentrated in the aqueous phase (Φ≥80%v). It has been ascertained by optical microscopy that passing at aqueous phase towords outside was very rapidy in the beginning due to coalescence, until the reverse emulsion diluted (Φ ≤30%v), but after that the process became very slaw.