Investigation of the tetraethoxysilane‐derived sol–gel process by rheological oscillation test and the effect of different synthetic parameters

Abstract

AbstractThe tetraethoxysilane (TEOS)‐derived sol–gel process was systematically investigated by the rheological oscillation test and the effect of different synthetic parameters, including TEOS concentration, water content, base catalyst concentration and temperature, on the viscoelastic properties of the formed gel was analyzed. It is found that the rheological oscillation test provides an efficient and accurate way to determine the gelation time in the sol–gel process. The time at which the storage modulus and loss modulus intersect can be regarded as the gelation time in the sol–gel process and it matches well with the time observed with the naked eyes. Furthermore, both the increased TEOS and base catalyst concentration can be beneficial to the improvement of the gel elasticity, which could be related to the increased concentration of silica primary particles and its condensation reaction rate. However, the increased water content and temperature lead to a first increase and then a decrease in the elasticity of the gel. The proper molar ratio of TEOS to water is 0.67:4.01 and the suitable reaction temperature is 318 K in this study.