Multiwave rheology and dynamic light scattering characterizations for a two-step sol-gel transition of tetraethoxysilane hydrolysis and condensation.

Abstract: In this article, we studied the multiwave rheology properties of a two-step tetraethoxysilane (TEOS) hydrolysis, as well as condensation processes and optimized particle synthesis conditions by focusing on the colloidal particle aggregation and growth behavior. Combining with the dynamic light scattering (DLS) technique, we systematically investigated the gelation process, network structure, overall apparent activation energy, DLS size growth trend and complex viscosity. Our results revealed that the overall apparent activation energy of the two-step-catalyzed process was lower than that of the single step and the gelation time was decreased with an increase in water-TEOS molar ratio. During our studies, we successfully simplified the rheological measurement for the two-step process by setting the base addition moment as the zero time. This method can also be applied for structure and density tuning, providing a new path to successfully synthesize customized materials in a sol-gel process.The five-stage scheme of the sol-gel transition. The viscosity and DLS size curves were divided into five parts. Based on this route and combined with rheological measurements, the control of our sol-gel process can be realized and eventually obtained desired features. Investigate the gelation time and the gel structure of a two-step sol-gel process by combining MWDT with DLS method.The rheological measurement for the two-step process was simplified by setting the base addition moment as the zero time.The synthetic strategy can be applied to other sol-gel systems for structure and density tuning. [ABSTRACT FROM AUTHOR]