Nucleation and Coalescence of BaTiO3 Using a Continuous Flow Reactor with Water-Ethanol Mixed Solvents

BaTiO3 formation was studied using a continuous flow reactor and water-ethanol mixed solvents exhibiting varying dielectric properties. The conditions under which BaTiO3 forms were explored by changing the solvent composition and the precursor concentration. Higher precursor concentrations were required for BaTiO3 formation in water-rich solvents than in ethanol-rich solvents. Moreover, smaller particles were obtained with increasing ethanol fraction, and they showed less growth, depending on the reaction time. Furthermore, the particle size decreased with an increase in precursor concentration in ethanol-rich solvents. In parallel to the experiments, a surface energy simulation using an implicit solvent model was conducted, considering the dielectric properties of the solvents. When Ba ions were incorporated into the BaTiO3 phase, the particle adhesion increased and larger BaTiO3 particles formed. The smaller particle formation at higher precursor concentrations in ethanol-rich solvents suggests that the nucleation of larger BaTiO3 originates from these small particles. When the particle adhesion increased (lower surface energy and higher solubility) through a change in the solvent properties, collisions between particles resulted in a slight increase in their size through coalescence. The growth via particle collision was suppressed by the molecular effects imparted by the solvents attaching to the particle surface.

Automated summary

Formation of BaTiO3 was studied in water-ethanol mixed solvents with varying dielectric properties. Higher precursor concentrations in ethanol-rich solvents resulted in smaller particles, suggesting nucleation of larger BaTiO3 originates from these small particles. Collision-induced growth was suppressed by solvent effects, impacting particle size.