Hollow TiO₂/SiO₂ microspheres through reactive assembly at the interface of aqueous droplets

The self-assembly is an important bottom up approach to achieve materials for various applications. In this work, we report a new method to achieve silica/titania core-shell hollow microspheres through a self assembly process at the interface of micrometric droplets. This method proves to be facile and scalable for achieving micron size composite hollow spheres. The diffusion reactant molecules across the phase boundary of interface of two immiscible liquids play crucial role to achieve such morphology. In this case, chemical reaction occurs only at the interface of the two phases. This opens a plethora of new opportunities to achieve variety of new materials. Silica/titania composite provides excellent thermal stability against the anatase to rutile phase transition due to inhibition of nanoparticle growth and leads to better photocatalytic properties of TiO₂. The electron microscopy complemented by small-angle neutron scattering reveal the hierarchical structure of the microspheres. (author)