Selective removal of particle cores to fabricate manganese carbonate hollow spheres and composite microcapsules

We report here the finding of different dissolution rate between the core and shell of a manganese carbonate particle, which was prepared by mixing NH4HCO3 and MnSO4 at room temperature. Based on the results of X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), we believe that the denser crystallites in the shells have a stronger stability against acid decomposition compared with the randomly and loosely assembled crystallites in the particle cores. Hollow spheres were then fabricated by utilizing the difference of decomposition rate between the particle shells and the cores in acidic solution at room temperature. Furthermore, by incorporating polyelectrolyte multilayers onto the particles prior to core decomposition, hybrid organic/inorganic hollow spheres were successfully produced.