Adsorption of Hydrophilic Silica Nanoparticles at Oil-Water Interfaces with Reversible Emulsion Stabilization by Ion Partitioning

Autor: Robert K. Keane, Wei Hong, Wei He, Sam Teale, Robbie Bancroft, Anthony D. Dinsmore
Rok vydání: 2022
Předmět:
Zdroj: Langmuir : the ACS journal of surfaces and colloids. 38(9)
ISSN: 1520-5827
Popis: Adsorption of particles at oil-water interfaces is the basis of Pickering emulsions, which are common in nature and industry. For hydrophilic anionic particles, electrostatic repulsion and the absence of wetting inhibit spontaneous adsorption and limit the scope of materials that can be used in emulsion-based applications. Here, we explore how adding ions that selectively partition in the two fluid phases changes the interfacial electric potential and drives particle adsorption. We add oil-soluble tetrabutyl ammonium perchlorate (TBAP) to the nonpolar phase and Ludox silica nanoparticles or silica microparticles to the aqueous phase. We find a well-defined threshold TBAP concentration, above which emulsions are stable for months. This threshold increases with the particle concentration and with the oil's dielectric constant. Adding NaClO
Databáze: OpenAIRE