Formation Mechanism and Dispersion of Pseudo-Tetragonal BaTiO3-PVP Nanoparticles from Different Titanium Precursors: TiCl4 and TiO2

Abstract

Nano-sized tetragonal BaTiO3 (BT) particles that are well dispersed in solution are essential for the dielectric layer in multilayer ceramic capacitor technology. A hydrothermal process using TiCl4 and BaCl2, as source of Ti and Ba, respectively, or the precursor TiO2 as seed for the formation of BT, and poly(vinylpyrrolidone) (PVP) as a surfactant, was employed in this study to enhance both the dispersibility and tetragonality (c/a) simultaneously in a single reaction process. The process parameters, i.e., the ratio of TiO2 substitution of TiCl4, the reaction time, and PVP content were systematically studied, and the growth mechanism and relation between the tetragonality and the particle size are discussed. Dynamic light scattering (DLS) analysis was used to show that truncated pseudo-tetragonal BT-PVP particles with an average size of 100 nm, having a narrow size distribution and a coefficient of variation (CV) as low as 20% and being mono-dispersed in water, were produced. The narrow particle size distribution is attributed to the ability of PVP to inhibit the growth of BT particles, and the high c/a of BT-PVP to heterogeneous particle growth using TiO2 seeds.

The role of pH-induced tautomerism of polyvinylpyrrolidone on the size, stability, and antioxidant and antibacterial activities of silver nanoparticles synthesized using microwave radiation

“…18 Several parameters can also affect the shape and size of the synthesized AgNPs, such as the molecular weight, PVP concentration, and solvent. [19][20][21] PVP is stable in the keto form at acidic pH, whereas the enol tautomer exists at pH 7 and is predominant at pH > 10. 22 The keto-enol tautomerism of PVP transforms its functional group to give it different properties when it interacts with precursors.…”

“…18 Several parameters can also affect the shape and size of the synthesized AgNPs, such as the molecular weight, PVP concentration, and solvent. 19–21…”

TiO2-Seeded Hydrothermal Growth of Spherical BaTiO3 Nanocrystals for Capacitor Energy-Storage Application

“…Because of the diversity of the factors that affect the synthesis of BaTiO 3 nanoparticles, hydrothermal methods are full of opportunities to improve their quality in phase composition, dimensions, and morphology. Li et al [35] reported the synthesis of tetragonal BaTiO 3 nanocrystals using TiCl 4 (or TiO 2 ) as the source of titanium, BaCl 2 as the source of barium, and polymer(vinylpyrrolidone) (PVP) as the surfactant. Grendal et al [36] used two titanium sources of amorphous titanium dioxide and a Ti-citrate complex solution to synthesize BaTiO 3 nanoparticles with a size range of 10-15 nm at different hydrothermal temperatures and times.…”