Theoretical and Experimental Investigations of Double Emulsion Preparation by Ultrasonication

Abstract

Double emulsion preparation by ultrasonication is investigated in order to optimize the outer droplet size and the encapsulation efficiency. The effects of the sonication time, the oil viscosity, and the fractions of salt and primary emulsion are studied. A correlation is developed in order to predict the mean droplet diameter as a function of these parameters. The model is valid in the dissipation energy subrange. It accounts for the effects of salt within the surface force group, the oil viscosity within the viscous group, and the primary fraction through energy damping and allows the prediction of the transitionary change in size with time. The properties of the outer droplets, such as the viscosity and density, take into account the presence of inner droplets. Based on this model, a leakage model is proposed where the rate increases proportionally with breakage, but continues at a constant rate once the size reaches equilibrium.

Preparation of stable multiple emulsions using food-grade emulsifiers: evaluating the effects of emulsifier concentration, W/O phase ratio, and emulsification process

“…It is also shown that the oil phase can contain one and/or multiple water droplets depending on the emulsion type. These results agree well with the literature, showing the formation of multiple emulsions using microscopy techniques [23,24]. We note that the higher stability at the higher concentration (50 wt%) of primary emulsion can be associated with increased solution viscosity due the larger volume fraction of dispersed phase [17].…”

Formulation and Preparation of Water-In-Oil-In-Water Emulsions Loaded with a Phenolic-Rich Inner Aqueous Phase by Application of High Energy Emulsification Methods

“…Under suitable homogenization conditions, the final droplet size depends strongly on the characteristics of the oil and emulsifier used [ 34 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 ]. In general, small droplet sizes can be obtained more effectively by low-energy approaches than by high-energy approaches, but the former are more limited in the types of oils and emulsifiers that can be used [ 11 ].…”

Evaluating the Stability of Double Emulsions—A Review of the Measurement Techniques for the Systematic Investigation of Instability Mechanisms

“…Interactions between coalescence and diffusion are described in literature for several formulations: when the inner water droplets coalesce, and thus increase their size, release is increased as well [21]. Khadem et al [22] reported the spontaneous breakdown of the double emulsion structure after a certain degree of osmotic swelling of the inner water droplets. These examples illustrate that the initial instability mechanism can be different from the observed result.…”