(70ah) Synthesis of Nanosize Hollow Silica Particle and Its Applications

Hollow particles are highly paid attention, because of excellent properties such as low density, high specific surface area, adsorption capacity, ability of encapsulating. However, the synthesis method to obtain nanosize hollow particle with productivity and low cost has not developed sufficiently. In this paper, the preparation of nanosize hollow silica particle using nanosize calcium carbonate particle as a core template is shown. CaCO3-SiO2 core-shell particle was prepared by the hydrolysis and polymerization of tetraethoxysilane (TEOS) in the suspension of nanosize calcium carbonate particle. Calcium carbonate of core particle was dissolved by hydrochloric acid, and hollow silica particle was obtained. This synthesis method was applied to the CaCO3 template particle of the several shapes. As the results, hollow silica particles with cubic shape, tube shape and sphere shape were obtained. Their hollow particles are used for the composite of nanosize particle and polymer. In this case, the surface characterization is important to disperse into polymer. Most of silica particles generated by sol-gel method are hydrophilic. The interaction force between particles in organic substance always works as attractive force, because there is no electric repulsion force such as the force generated by electric double layer on the particle surface in aqueous solution. Therefore, it is difficult to disperse them into polymer. We characterized the surface by both adsorption technique and spectroscopic method, and revealed their real surface. The dispersability of hollow particle was improved by chemical surface modification technique based on surface characterization. We will also show you the new direction of particle dispersion technique based on surface characterization in this paper.