A novel microfluidic technology for the preparation of gas-in-oil-in-water emulsions

Abstract

This paper presents a novel microfluidic method for the controllable generation of uniform gas-in-oil-in-water double emulsions with ultra-thin liquid films (2–12 μm) covering microbubbles (116–180 μm). This method combines one dispersion stage and a mass transfer-induced phase separation process in a simple co-flowing microchannel, instead of a complicated microfluidic device fabrication and a multistage dispersion process. In our experiments, CO₂–alkane gas mixtures (dispersed phase) and NaOH aqueous solutions (continuous phase) were utilized as working systems. The main factors affecting the diameter of the inner bubble and the volume of the oil film are discussed. Through our method, the monodispersed gas-in-oil-in-water emulsions can be prepared in a simple and precise way.