Development of preparation method to control silica sol–gel synthesis with rheological and morphological measurements

• We prepared silica sols with sodium silicate and sulfuric acid by a Y-shaped reactor.
• Controlling the pH can change the gelling time, gel structure, and powder property.
• The addition of NaCl can change the gelling time and the gel instantaneous modulus.

In this paper, we report the effects of pH and salt on the gelling properties of silica (SiO2) sols and gels which were measured both by dynamic viscoelasticity measurement and by creep test equipment. The network structures built by SiO2 particles formed under different conditions were observed by a scanning probe microscope (SPM). N2 adsorption measurements were also conducted in order to analyze the characteristics of dried gel powders including specific surface area, pore volume, and pore size distribution. The objective of this study is to characterize the SiO2 sol, gels, and powders obtained by a Y-shaped reactor under different pH and salt conditions.

Rheological properties of silica sols with different preparation conditions.Figure optionsDownload as PowerPoint slide