Ultrasound assisted preparation of emulsion of coconut oil in water: Understanding the effect of operating parameters and comparison of reactor designs

• Ultrasound assisted preparation of nanoemulsions.
• Understanding the effect of operating parameters on droplet size distribution.
• Experiments at different scales of operation using different reactors.
• Internal phase fraction and emulsifying agent loading are critical parameters.
• Critical minimum droplet size exists depending on the set of operating parameters.

The present work investigates the application of different sonochemical reactor designs for the preparation of stable nanoemulsions considering the emulsion of coconut oil in water as the model system. The effect of different operating parameters as well as chemical compositions on the stability and droplet size of emulsion has also been investigated. Different processing capacities over the range of 50mL–2 L have been used with different power ratings for the sonochemical reactors. Two emulsifying agents viz. Tween 80 and Span 80 were used to prepare stable emulsions and the effect of emulsifying agent volume fraction on the emulsion droplet size has been illustrated. Zeta sizer has been used to measure the droplet size and distribution of internal phase of emulsion. Intensity mean diameter has been used to compare the droplet size distribution of the nanoemulsion formed using different sonochemical reactors. Power dissipated per unit volume of emulsion has been considered as the unified criteria for understanding the dependency of the prepared emulsions on the type of sonochemical reactor designs.