Effect of Emulsification Conditions on the Properties of Microspheres Prepared by a Solvent Extraction Process

Abstract

Microspheres can be prepared using a hydrocarbon-perfluorocarbon-based solvent extraction process. The effect of changing the surfactant amount, emulsification temperature, and stirring speed on the size of microspheres was investigated. The surfactant concentration was found to greatly affect the microsphere size and size distribution. The Sauter mean diameter of the microspheres decreased exponentially as a function of surfactant concentration. The microsphere size distribution became narrower with increasing surfactant concentration. A clear correlation between the Sauter mean diameter of the microspheres and the Weber number was found. A surfactant concentration was identified at which the size of microspheres remained constant although the Weber number was changed. Finally, a lower emulsification temperature decreased the coalescence of the droplets and microspheres with smaller Sauter mean diameter were produced when using a low surfactant concentration.

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