Rheological characterization of BaTiO3 sol-gel transition

• Published in: Journal of sol-gel science and technology Vol. 9; no. 1; pp. 5 - 15
• Main Authors: Brasseur, A., Michaux, B., Pirard, R., Van Cantfort, O., Pirard, J. P., Lecloux, A. J.
• Format: Journal Article Web Resource
• Language: English
• Published: New York Springer Nature B.V 01.01.1997; Springer
• Subjects: Barium hydroxide; barium titanate; Barium titanates; Chemical engineering; Dilution; Engineering, computing & technology; Gelation; Gels; Growth models; Ingénierie chimique; Ingénierie, informatique & technologie; Materials science & engineering; Moisture content; Polycondensation reactions; Rheological properties; Rheology; Science des matériaux & ingénierie; sol-gel; Sol-gel processes; Viscoelasticity
• ISSN: 0928-0707; 1573-4846; 1573-4846
• DOI: 10.1007/BF02439331

BaTiO3 gels were prepared by hydrolysis and polycondensation reactions between titanium isopropoxide and barium hydroxide in presence of methoxyethanol, methanol and water. The rheology of the sol-gel transition was studied with a rheometer allowing low amplitude sinusoidal oscillations. Experimental data show a continuous increase in the complex viscosity along with time, showing the progressive character of the transition. The influence of synthesis operating variables was studied. The gelation time, which definition is based on viscoelastic measurements, increases exponentially when the water content is increased, when the dilution due to the methoxyethanol is reduced or when the temperature is lowered. Different growth models were used for the characterization of the particles in the solution. These models suggest that the polymerisation first produces spherical particles (mass fractals) and that these spherical particles then agglomerate to form a linear network.