Effect of PVP on the synthesis of high-dispersion core-shell barium-titanate-polyvinylpyrrolidone nanoparticles

Monodispersed nanoparticles consisting of barium titanate (BaTiO3, BT) as the core and polyvinylpyrrolidone (PVP) as the shell were synthesized in a PVP-assisted low-temperature process in an aqueous solution at ambient pressure. In order to clarify the mechanism of this unique BT-PVP nanoparticle growth and the origin of the dispersion, the concentration and molecular weight of PVP used in the synthesis were varied, and the size and dispersion of the resulting nanoparticles in water were investigated by field-emission scanning electron microscopy and dynamic light scattering. Monodispersed nanoparticles with an average size of 130 nm were obtained by using an intermediate PVP concentration of 100 g/L and a PVP molecular weight of 10,000 g/mol. The thickness of the PVP shell was estimated by thermogravimetric analysis. For the highly dispersed BT-PVP, the thickness of PVP adsorbed on the BT surface was around 3-5 nm. Direct SEM observation of monodispersed BT-PVP in an aqueous solution using a unique sample holder was also demonstrated for the first time.