Pickering particle and emulsifier co-stabilised emulsions produced via rotating membrane emulsification

Producing stable particle-stabilised emulsions of small droplet sizes and high monodispersity via membrane emulsification approaches is hindered by the poor mixing environment during processing and the low diffusivity and minimal interfacial tension lowering capacity of colloidal particles. The present study investigates the co-stabilisation (particles and emulsifiers) of O/W emulsions formed by rotating membrane emulsification. Formulation aspects of the employed co-stabilisation strategy (type/concentration of emulsifiers and type/size of particles) were assessed at a fixed trans-membrane pressure (10 kPa) and rotational velocity (2000 rpm). Emulsion microstructure was shown to be affected by the occurrence of emulsifier/particle interactions. In formulations where these interactions are synergistic and emulsifier content is low, interfacial stabilisation is carried out by both species and resulting emulsions possess smaller droplet sizes, higher monodispersity indices and enhanced stability against coalescence, compared to systems stabilised by either of the two components alone. This work concludes that a carefully controlled co-stabilisation strategy can overcome the current challenges associated with the production of particle-stabilised emulsions via membrane emulsification methods.