High-Yield Synthesis of Janus Dendritic Mesoporous Silica@Resorcinol-Formaldehyde Nanoparticles: A Competing Growth Mechanism.

Recently, Janus nanostructures that possess two or more different surface functions have attracted enormous attention because of their unique structures and promising applications in diverse fields. In this work, we present that Janus structured dendritic mesoporous silica@resorcinol-formaldehyde (DMS@RF) nanoparticles can be prepared through a simple one-pot colloidal method. The Janus DMS@RF nanoparticle shows a bonsai-like morphology which consists of a dendritic mesoporous silica part and a spherical RF part. After a systematic study on the growth process, we proposed a competing growth mechanism that accounts for the formation of Janus nanostructures. It is believed that suitable polymerization rate of silica and RF resin is critical. Based on the competing growth mechanism, eccentric and concentric core-shell nanostructures have been successfully prepared by tuning the polymerization rates of silica and RF, respectively. Metal-contained ternary Janus nanoparticles that might be used for catalysis have also been prepared. This research may pave the way for the practical applications of delicate nanomaterials with desired structures and properties.