Synthesis of BaTiO₃ nanoparticles as shape modified filler for high dielectric constant ceramic-polymer composite

Coral-like structured barium titanate (BaTiO₃) nanoparticles were synthesized as filler for a high dielectric elastomer. The nanoparticle size, and shape, and the reactivity of the synthesis were modified according to temperature, time, pH, and precursor materials. Dielectric properties of poly(dimethylsiloxane) (PDMS) composites were estimated by volume fractions of BaTiO₃ of 5, 10, and 15 vol% for both sphere and coral-like shapes. As a result, coral-like BaTiO₃-PDMS composites had the highest dielectric constant of 10.97, which was 64% higher than the spherical BaTiO₃-PDMS composites for the 15 vol% fraction. Furthermore, the phase transition process and surface modification were applied to increase the dielectric properties through calcination and improved particle dispersion in the elastomer using polyvinylpyrrolidone (PVP). The dispersion of the PVP coated BaTiO₃-PDMS composite was improved compared to pristine BaTiO₃ as shown by SEM imaging. The coral-like BaTiO₃ embedded composite could be used for electronic devices such as piezoelectric devices or electro-adhesive grippers, which require flexible and high dielectric materials.