Synthesis and study by electron microscopy of inverse opals from zirconium oxide

Zirconia has a high dielectric constant and high thermal stability. There are many methods for the synthesis of nanocrystalline materials from zirconium dioxide. These include hydrothermal synthesis, gasphase chemical reactions, cryochemical synthesis, plasma chemistry methods - these methods are expensive and complex. In this work, we propose a relatively simple method for controlling the growth of zirconium dioxide nanocrystals by synthesis in polymer templates (template synthesis of inverse opals). Inverse opals have unique physical and chemical properties, so they can be widely used in optics, optoelectronics, biological research, catalysis, functional ceramics, which is also relevant in the rocket and space industry. As a starting material, we used a water-alcohol solution of zirconium oxychloride, with which we impregnated templates of monodisperse submicron spherical particles of polymethyl methacrylate. After impregnation of these templates, the solution solidified in a limited pore space of 20-40 nm. After that, we fired the resulting templates to remove the polymer matrix. In this case, structures consisting of zirconium dioxide nanocrystals were formed. Using the methods of scanning and transmission electron microscopy, we assessed the morphology of the obtained materials, and showed that under conditions of limited diffusion, zirconium dioxide forms crystals with a size of 10-30 nm. Also, depending on the calcination temperature, materials with different crystalline modifications are obtained. As a result, we have shown that aqueous-alcoholic solutions of zirconium oxychloride are a convenient means for obtaining nanocrystalline materials, including inverse opals from zirconium dioxide, by template synthesis.