Preparation of monodisperse spherical SiO2 and rheological property of its suspension

Monodisperse SiO2 spherical particles were prepared by sol-gel using hydrolyzation of TEOS in ethanol, with ammonia as activator. The influence of silane coupling agent on the dispersibility of SiO2 powder was studied. The two kinds of powders prepared without dispersant and prepared with silane coupling agent were characterized with transmission electron microscrope (TEM) and the powder dispersed by silane coupling agent was characterized with X-ray diffraction (XRD) and infrared spectrum (IR). The rheological property of SiO2/PEG suspension was studied by stress controlled rheometer. The results show that the silane coupling agent improves dispersibility of SiO2 powder obviously. The monodisperse sphere particles dispersed by silane coupling agent is amorphous. The SiO2/PEG suspension shows shear thinning and reversible shear thickening behavior.