(228b) Hydrotalcite Film Fabrication By Secondary Crystal Growth and Analysis of Crystal Growth Kinetics

Hydrotalcite films have attracted considerable attention due to their unique properties and industrial application such as catalysts, anti-coating materials, electrodes, sensors, and membranes. Hydrotalcite films are usually prepared by two conventional methods: physical deposition or in-situ synthesis. In the physical deposition method, film is formed by deposition of pre-synthesized seeds using solvent evaporation, spin coating, layer-by-layer assembly or Langmuir-Blodgett method and the properties of film can be controlled in the hydrotalcite synthesis process. On the other hand, an in-situ synthesis can be applied by directly synthesizing hydrotalcite film on the substrate and this method enhances the mechanical stability of the film. However, these conventional methods have difficulties due to the weak interaction between particles and limited synthetic conditions. In this study, to overcome these drawbacks, we fabricated hydrotalcite film by means of secondary crystal growth for the first time. First, hydrotalcite seeds were synthesized and deposited on the alumina substrate, and then hydrotalcite film was fabricated by hydrothermal treatment in an autoclave for the growth of hydrotalcite. In the secondary crystal growth, the morphology change of hydrotalcite film was observed by scanning electron microscopy (SEM) and the structural change of hydrotalcite film was confirmed by X-ray diffraction (XRD). For the kinetic analysis, particle size and size distribution were measured from SEM images with time and different kinetic models were fitted to the experimental data to find the best model for describing secondary crystal growth process.