Interfacial solute flux promotes emulsification at the water|oil interface.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 36759528.
- Also identified by DOI 10.1038/s41467-023-35964-9 and PMC identifier 9911786.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Emulsions are critical across a broad spectrum of industries. Unfortunately, emulsification requires a significant driving force for droplet dispersion. Here, we demonstrate a mechanism of spontaneous droplet formation (emulsification), where the interfacial solute flux promotes droplet formation at the liquid-liquid interface when a phase transfer agent is present. We have termed this phenomenon fluxification. For example, when HAuCl4 is dissolved in an aqueous phase and [NBu4][ClO4] is dissolved in an oil phase, emulsion droplets (both water-in-oil and oil-in-water) can be observed at the interface for various oil phases (1,2-dichloroethane, dichloromethane, chloroform, and nitrobenzene). Emulsification occurs when AuCl4- interacts with NBu4+, a well-known phase-transfer agent, and transfers into the oil phase while ClO4- transfers into the aqueous phase to maintain electroneutrality. The phase transfer of SCN- and Fe(CN)63- also produce droplets. We propose a microscopic mechanism of droplet formation and discuss design principles by tuning experimental parameters.