Project

Using microfluidics to study emulsifier adsorption and emulsion stability

Microfluidics can be used to produce emulsions but also to study the stability of emulsion droplets during production and further processing [1]. In this project we focus on the use of microfluidic tools to study emulsifier adsorption and emulsion stability. Measurements are done with a microfluidic Y-junction and coalescence channel. Results are related to industrial processing conditions in order to gain understanding of emulsification at relevant time and length scales.

Figure 1; Interfacial tension of 0.3 wt. % SDS as a function of the droplet formation time with microscope pictures taken directly after droplet formation with their droplet formation time indicated [3].
Figure 1; Interfacial tension of 0.3 wt. % SDS as a function of the droplet formation time with microscope pictures taken directly after droplet formation with their droplet formation time indicated [3].
Figure 2; Layout of the microfluidic coalescence channel [5].
Figure 2; Layout of the microfluidic coalescence channel [5].

Based on previous work in our group [2] we developed a microfluidic method to measure interfacial tension in time scales relevant for industrial emulsification (i.e., sub-milliseconds to milliseconds) [3]. The method is based on the relation between droplet size and the continuous phase velocity and viscosity, dispersed phase flow rate and the interfacial tension between the two fluids at the moment of detachment. Accurate measurements are possible because of the high monodispersity of the formed droplets and advanced image analysis (Clip 1). Figure 1 illustrates typical results found with this method, for example with sodium dodecyl sulphate (SDS) used as a model emulsifier. Our next steps are to gain better understanding of emulsifier transport mechanisms in the microfluidic device, and to apply this method to study the adsorption of food-grade emulsifiers.

Acknowledgements

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This work is supported by NanoNextNL, a micro and nanotechnology consortium of the Government of the Netherlands and 130 partners.

References