Silicic Acid Polymerization and SiO₂ Nanoparticle Growth in Hydrothermal Solution

Area of Science:

• Materials Science
• Chemical Engineering
• Computational Chemistry

Background:

• Orthosilicic acid (OSA) polymerization is a key process in silica (SiO2) nanoparticle formation.
• Controlling nanoparticle size and distribution is crucial for applications in hydrothermal synthesis.

Purpose of the Study:

• To develop a numerical simulation model for OSA polymerization and SiO2 nanoparticle formation.
• To investigate the influence of various parameters on nanoparticle characteristics.

Main Methods:

• Numerical simulation based on homogeneous nucleation and particle growth models.
• Evaluation of surface tension, molecular deposition rate, and Zeldovich factor.
• Verification with experimental data including dynamic light scattering.

Main Results:

• Identified temperature, pH, initial OSA concentration, and ionic strength as critical factors.
• Established relationships between these parameters and colloid phase formation kinetics, nanoparticle size, and size distribution.
• Validated simulation results against experimental data across a wide range of conditions (20-180 °C, pH 3-9).

Conclusions:

• The developed numerical model accurately predicts SiO2 nanoparticle formation during OSA polymerization.
• Results provide a basis for controlling nanoparticle properties in hydrothermal synthesis of sols, gels, and nanopowders.