Particle morphology dependent dielectric properties of CaCu₃Ti₄O₁₂/polyvinyl alcohol composite films

Flexible dielectrics with high dielectric constant and low loss have promising applications in many electronic devices. In this work, a binary composite with admirable dielectric properties was fabricated using a giant dielectric material CaCu₃Ti₄O₁₂ (CCTO) as the filler and a non-ferroelectric and water-soluble polymer, polyvinyl alcohol (PVA) as the matrix. To optimize the dielectric properties, the effects of CCTO particle morphology on the dielectric properties of the CCTO/PVA composite films were detailed with the help of X-ray diffraction, scanning electron microscopy, and precision impedance analyzer. Compared with CCTO/PVA composite films filled with rod-shaped or irregular CCTO particles, composite films filled with square CCTO particles exhibited the highest dielectric constant and the maximum dielectric constant reached up to 45.5 while the dielectric loss was only 0.19 at 100 Hz. This work provides a promising way to fabricate PVA-based dielectric composites for practical applications in electronics.