[Abstract]

We present a new strategy that utilizes temperature-responsive wax-based Janus particles as microsurfactants to simultaneously achieve enhanced emulsion stability as well as on-demand coalescence of emulsion droplets. The dumbbell structure with different surface wetting properties on each side of the Janus particle enables the particles to strongly adsorb at the liquid-liquid interface, leading to excellent stability against coalescence for both water-in-oil (W/O) and oil-in-water (O/W) emulsions. Moreover, these Janus microparticles are composed of a hydrophilic acrylate resin and a hydrophobic wax compartment which transitions from a frozen to an oil-soluble molten state above the melting point. This allows the particle-adsorbed droplets to coalesce above a designated temperature, depending on the type of wax material used. We envision that the excellent emulsion stability and the tunable and rapid response to local temperature enabled by the wax-based Janus particle offers new and exciting opportunities in the advancing technologies including micro-reactors and drug delivery systems to name a few.

DOI: 10.1002/smll.202070267

LINK: https://onlinelibrary.wiley.com/doi/abs/10.1002/smll.202070267