Surfactant‐Assisted Emulsion Self‐Assembly of Nanoparticles into Hollow Vesicle‐Like Structures and 2D Plates

Abstract

The emulsion‐based self‐assembly of nanoparticles into low‐dimensional superparticles of hollow vesicle‐like assemblies is reported. Evaporation of the oil phase at relatively low temperatures from nanoparticle‐containing oil‐in‐water emulsion droplets leads to the formation of stable and uniform sub‐micrometer vesicle‐like assembly structures in water. This result is in contrast with those from many previously reported emulsion‐based self‐assembly methods, which produce solid spherical assemblies. It is found that extra surfactants in both the oil and water phases play a key role in stabilizing nanoscale emulsion droplets and capturing hollow assembly structures. Systematic investigation into what controls the morphology in emulsion self‐assembly is carried out, and the approach is extended to fabricate more complex rattle‐like structures and 2D plates. These results demonstrate that the emulsion‐based assembly is not limited to typical thermodynamic spherical assembly structures and can be used to fabricate various types of interesting low‐dimensional assembly structures.