Facile Fabrication of Monodisperse Micron‐Sized Dual Janus Silica Particles with Asymmetric Morphology and Chemical Environment

Abstract Janus particles are a kind of materials with asymmetric morphology or surface chemical environment. But so far, the preparation of particles with dual asymmetry is still a challenging problem. Hence the cation surfactant hexadecyl trimethyl ammonium bromide and co‐surfactant octadecylamine are applied to improve the Pickering emulsion stability, and the micron‐sized silica particles are arranged in a single layer at the toluene–water interface through electrostatic interaction. Furthermore, organosilane reagents are added in the preparation process, resulting in the construction of asymmetric hydrophilic or hydrophobic mesoporous precisely onto the micron‐sized silica particles surface. The cation surfactant‐assisted Pickering emulsion method is simple, effective, and convenience, which can be applied in the synthesis of various dual Janus silica particles for specific applications.