Tuning particle–particle interactions to control Pickering emulsions constituents separation

Abstract

We demonstrate that the separation and recovery of solid-stabilized (Pickering) emulsion constituents are significantly improved via a simple filtration approach – without any additional chemical agent – by initially grafting sodium alginate (SA), a natural polysaccharide, onto silane-modified sub-micrometer silica particles. The combination of surface-grafted trimethoxy(propyl)silane (TMPS) and (3-aminopropyl)trimethoxysilane (APTMS) controls particle wettability, verified via zeta potential and contact angle measurements. Rheometry and filtration experiments reveal that further grafting of SA via APTMS enhances particle–particle and droplet–droplet interactions. This work provides an approach towards the design of environmentally friendly Pickering emulsion based chemical engineering processes with easy-to-separate and reusable particles, allowing waste reduction and reduced toxicity advantages.