Multiple pickering high internal phase emulsions stabilized by modified diatomite particles via one-step emulsification process

Abstract

Conventional approaches to generating double emulsions are cumbersome, complicated, and based on a two-step emulsification process using a combination of two distinctive surfactants. In this work, the surface properties of diatomite particles were successfully tailored by chemical modification with palmitoyl chloride. The properties of the resulting diatomite particles changed from the original hydrophilicity to hydrophobicity, leading to straightforward stabilization of oil-in-water-in-oil (O/W/O) Pickering double emulsions by a one-step emulsification process. Pickering double high internal phase emulsions (HIPEs) with an internal phase up to 80 vol% could be produced solely using the modified diatomite particles. The water-in-oil (W/O) droplet sizes of these HIPEs were much larger than the droplets of conventional nanoparticle-stabilized Pickering HIPEs. Furthermore, using the O/W/O Pickering double emulsions as templates, the porous polymer particles were fabricated. In addition, it was demonstrated that the wide particle size distribution of diatomite particles and modified heterogeneity were the reasons for the formation of multiple emulsions.