Tuning particle-particle interactions to control Pickering emulsions constituents separation

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.