Production of solid-stabilised emulsions through rotational membrane emulsification: influence of particle adsorption kinetics

Abstract

There is currently a significant interest in the production of stable emulsions using particulate emulsifiers. A key design and manufacturing challenge in such systems is the production of emulsions with controlled droplet sizes and narrow polydispersity; one candidate production technique is membrane emulsification. In this study we demonstrate that under optimal conditions, highly stable near monodisperse tricaprylin droplets stabilised with 800 nm silica colloids can be achieved using Rotating Membrane Emulsification (RME). We report the influence of various mechanical and chemical parameters on the droplet sizes and size distributions. The optimal conditions for highly stable emulsions with narrow size distributions using the RME approach are described. Investigating the rotational speed and particle concentration in particular highlights the importance of particle adsorption kinetics onto a growing droplet on the detachment of that droplet from the membrane. The data clearly show that if the particles attach and adsorb to the interface before a critical droplet detachment time, stable monodisperse droplets are produced. However, if the adsorption time takes longer than this critical value, the partially stabilized droplets can coalesce and we observe a wider size distribution.