Controlled release of precipitating agents through solvothermal destabilization of microemulsions:: one-pot synthesis of monoclinic zirconia nanostructures

We report a versatile one-step multiphase approach to control size, crystallinity and assembly at the nanoscale. The method takes advantage of the controlled release of precipitating agents achieved through the solvothermal destabilization of reverse microemulsions. This method permits the preparation of nanoparticles (as an example we prepare zirconia materials) self-assembled in open (palmate leaf-like) and compact nanostructures that could be easily processed using existing solution routes. The mechanisms of formation of these nanostructures are presented on the basis of the structural information and surface charge data provided by various techniques. The morphology of the nanostructures is found to be the combined result of several growth features, among which self-assembly driven by electrostatic forces plays a critical role. In addition, we have found that more open nanostructures lead to monoclinic zirconia samples with a higher degree of crystallinity, which supports the idea that surface energy must play a critical role in the stabilization of tetragonal polymorphs or amorphous zirconia phases.