Synthesis and size control of monodispersed BaTiO₃–PVP nanoparticles

Abstract

Monodispersed, spherical nanoparticles of the BaTiO 3-polyvinylpyrrolidone (BT-PVP) composite were synthesized through the surface modification of the oxide BT by the polymer PVP, using TiCl 4 , BaCl 2 , PVP, and KOH (as the mineralizer) in an aqueous solution. To reduce the size of the particles and ensure that they were monodispersed, the concentrations of the Ba and Ti sources were increased and the reaction parameters such as reaction temperature, reaction time, and KOH concentration were optimized. As a result, monodispersed BT-PVP particles with an average diameter of 114 nm (coefficient of variation, CV = 20.0%) were obtained from a Ba-rich solution ([Ti]/[Ba] = 0.2 M:0.3 M; [KOH] = 1.4 M), and their dynamic light scattering in an aqueous suspension demonstrated that the average diameter was 162 nm (CV = 26.6%). A higher KOH concentration resulted in smaller particles, but the excess KOH promoted particle aggregation and PVP gelation. The mechanism of dispersion and aggregation of BT-PVP will be discussed in detail.

Synthesis of highly disperse tetragonal BaTiO3 nanoparticles with core–shell by a hydrothermal method

“…PVP is widely used as a stabilizer, which prevents nanoparticle aggregation via PVP steric effect. For the BT-PVP particles prepared at a relatively low temperature (80 • C) and atmospheric pressure in our previous study, no changes in the chemical structure of the PVP layer adsorbed on the BT surface via hydrogen bonding between the OH group of BT species and C O groups of PVP molecules were detected [15]. Izu et al [27] reported the PVP cross-linking observed on the surface of CeO 2 nanoparticles, which were prepared in ethylene glycol at a temperature of 190 • C and atmospheric pressure.…”

“…Very few research studies about polyvinypyrrolidone (PVP) was utilized as a dispersant for BT nanoparticles, although PVP has been widely used in the synthesis of metal and other metal oxide nanoparticles as a stabilizer, template, and inhibitor of particle growth. In a previous study, we have reported the synthesis of highly disperse BT-PVP nanoparticles at temperature below 100 • C and atmospheric pressure that PVP served as a stabilizer and inhibitor [14], through adsorbed on the BT surface via hydrogen bonding [15]. The dispersion of the synthesized nanoparticles was achieved via the PVP steric effect; however, the phase of the BT-PVP obtained at low temperatures was cubic.…”

Thin Film Coating with Highly Dispersible Barium Titanate-Polyvinylpyrrolidone Nanoparticles

“…This induces defects in the thin films and imparts an uneven surface, and the nanoparticles cannot exhibit their inherent characteristics, which reduces the performance of the electrical components. In order to solve this problem, highly dispersible BT nanoparticles were prepared with polyvinylpyrrolidone (PVP) by the low temperatures synthesis (LTS) and hydrothermal (HT) process, referred to as LBT-PVP and HBT-PVP respectively, as reported in our previous paper [ 21 , 22 ]. The nanoparticles prepared by these methods can be dispersed as suspension in a coating slurry, and with these particles thin film layers can be prepared easily and quickly by a bar coating process as Itoh et al reported [ 23 ].…”

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

“…The method, which succeeded in solving the problem of a fine particle size and dispersion in one step, was motivated by the core-shell particle process proposed by Izu et al [ 15 ]. Other authors attempting to obtain smaller high-dispersion nanoparticles prepared highly dispersed 80-nm-sized cubic BT-PVP particles by controlling the reaction parameters and the metal ion concentration in solution [ 16 , 17 ].…”

“…Two well-known approaches were proposed in the form of an in-situ reaction and dissolution-precipitation reaction for the growth of BT in a hydrothermal process [ 16 ]. To understand which one prevails and which one leads to high-quality BT, the use of various sources of Ti and the ratio of Ti to Ba were studied, with TiO 2 frequently used as the source of Ti raw material [ 18 , 19 ].…”