Surface properties of nanosize hollow silica particles on the molecular level

Hollow particles are a newly developing material with the special properties of low density, thermal insulation and distinct optical activity. A number of preparation methods have been proposed in the literature. The polymer bead template method is one of the common processes to synthesize hollow particles, which can easily control particle size. However, byproducts produced during preparation adversely affect the natural environment. We have proposed an inorganic template method which overcomes the above disadvantages and also has some strong points. Although particle surface structure strongly affects wettability and particle dispersability, there are few reports that have discussed hollow particle structure. In this study, the shell wall structure of hollow particles was determined in detail by an analysis adsorption mechanism using the nitrogen adsorption isotherm. The results were compared with those of dense particles. The characteristics of the surface hydroxyl groups which react with surface modification reagents were then evaluated by water vapor adsorption. The modified surface was also characterized by Fourier-transform infrared spectroscopy and thermogravimetry/differential thermal analysis.