Characterization of Emulsions: A Systematic Spectroscopy Study

Emulsification processes results in the generation of droplets populations produced from the dynamic equilibrium between the breakup and coalescence phenomena determined primarily by the formulation and composition variables, mixing characteristics and emulsion preparation. The information contained in the UV‐vis spectrum on the absorption and scattering properties of the emulsions lead to the interpretation of the spectra in terms of the particle size distribution, the particle shape, and the chemical composition of the oil and emulsifier. This article reports analysis of emulsions on transmission spectrum as function of the oil concentration and physicochemical variables. The quantitative interpretation of the transmission spectrum is performed in the portion where no absorption is present (300–820 nm) leading to reliable estimated of droplet size populations in the range of 1 to 20 µm. The possibility of obtaining information from a single multiwavelength measurement makes UV‐vis spectroscopy a powerful tool for characterization of dispersed systems.

Keywords:

• Emulsion
• droplet size
• multiwavelength spectroscopy
• particle characterization

The authors thank the Venezuelan National Research Fund (FONACIT‐Grant No. F‐2005000175) and to the University of the Andes Research Council (CDCHT‐Grant No. I‐817‐05‐08 B) for sponsoring the research program at the POLYCOL (Polymers and Colloids) Laboratory.