Facile synthesis of mesoporous organosilica nanobowls with bridged silsesquioxane framework by one-pot growth and dissolution mechanism

Abstract

Mesoporous organosilica materials with organo-bridged silsesquioxane and novel structures have attracted great attention due to combined or enhanced properties. Here, we achieved facile synthesis of uniform well-defined mesoporous organosilica nanobowls with ethane- or ethane&thioether-bridged silsesquioxane framework by one-pot reaction. The possible formation mechanism may be attributed to be a dynamic growth, dissolution and reassembly process, including a uniform coating of ethane-bridged organosilica on the surface of mesoporous silica nanoparticles (MSNs) or mesoporous organosilica nanoparticles (MONs), gradual dissolution of MSNs or MONs core for the collapse of hollow spheres, and regrowth and reassembly of a small portion of the dissolved species. The framework stability of MSNs can be regulated by adjusting the amount of introduction of thioether-bridged silsesquioxane in the framework from 0 to 100%, which determines the structures of finally obtained products (nanobowls or rough nanoparticle (NPs)). The interesting results shed light on fundamental mechanisms of growth and dissolution for design and synthesis of novel structured materials. The ethane&thioether-bridged nanobowls show good hemocompatibility and low cytotoxicity compared with ethane-bridged nanobowls and calcined MCM-41-typed MSNs. The unique nanobowl structure, worm-like mesochannels and silsesquioxane framework make it as potential candidates for nanobiomedical applications.