Double-faced γ-Fe2O3||SiO2 nanohybrids: flame synthesis, in situ selective modification and highly interfacial activity.

Double-faced γ-Fe2O3||SiO2 nanohybrids (NHs) and their in situ selective modification on silica faces with the 3-methacryloxypropyltrimethoxysilane molecules have been successfully prepared by a simple, rapid and scalable flame aerosol route. The double-faced NHs perfectly integrate magnetic hematite hemispheres and non-magnetic silica parts into an almost intact nanoparticle as a result of phase segregation during the preparation process. The unique feature allows us to easily manipulate these particles into one-dimensional chain-like nanostructures. On the other hand, in situ selectively modified double-faced γ-Fe2O3||SiO2 NHs possess excellent interfacial activities, which can assemble into many interesting architectures, such as interfacial film, magnetic responsive capsules, novel magnetic liquid marbles and so forth. The modified NHs prefer to assemble at the interface of water-oil or oil-water systems. It is believed that the highly interfacial active NHs are not only beneficial for the development of interface reaction in a miniature reactor, but also very promising functional materials for other smart applications.