Magnetic Field Effects in Pickering Emulsions Stabilized by Magnetic Janus Particles

Magnetic Janus particles have two regions with different surface properties in combination with their magnetic responsiveness. Interfacially active magnetic Janus particles with regions of different surface wettabilities anchor strongly at an oil-water interface and generate stable emulsions. Magnetic Janus particles are ideal emulsifiers for achieving emulsification/demulsification on demand, controlled by an external magnetic field. In-house synthesized magnetic Janus particles were used to stabilize decane droplets in water, developing magnetic Pickering emulsions. Droplet structures, deformation, coalescence, and breakage were studied with and without the application of an external magnetic field by exploring emulsion magneto-rheological behavior. Interfacial shear rheology and optical microscopy were also investigated. The results were used to define the stability criterion of magnetic Janus-particle-based Pickering emulsions under a magnetic field.