Authors: S.H. Wang, Y.S. Sun, A.S.T. Chiang
Affilation: National Central University, Taiwan
Pages: 233 - 236
Keywords: ZrO2, refractive index, dispersion
Previous products of nano-ZrO2 usually come in the form of dispersed sol. When they are to be used in organic/inorganic composite, the solvent accompanied may not be compatible with the target polymer system. We have developed a low temperature hydrothermal crystallization process to produce nano-ZrO2, from which re-dispersible powders could be prepared after carboxylic acid modification. By “re-dispersible”, we are referring to the situation that a slightly bluish but transparent sol containing more than 10 wt % of ZrO2 could be prepared by simply adding the powder into a solvent or monomer followed by a few minutes of ultrasonic agitation. SAXS, SANS and DLS analysis showed that the primary particle size of the dispersed ZrO2 was about 5 nm. Only a small fraction of the particles appeared as 10 to 15 nm size aggregates. Since their size depends on the ligand-solvent pair, they must be produced during the dispersion. Strong photoluminance between 400-460 nm was observed when irradiated with UV light. This was believed to come from the organic/inorganic complex, since the emission and excitation spectra were symmetric.