A Developed Rahaman Model for Estimating the Dielectric Permittivity of Polymer–Barium Titanate Nanocomposites

Abstract

A developed Rahaman model considering the interphase properties is proposed to estimate the dielectric permittivity of polymer− barium titanate (BT) nanocomposites. In this study, the ceramic BT nanoparticle and the interphase region surrounding the nanoparticle are regarded as an equivalent nanoparticle, which has a core−shell structure. The polymer−BT nanocomposite is assumed to be a homogeneous mixture of the polymer matrix and equivalent nanoparticles. The dielectric permittivity of the polymer−BT nanocomposite is calculated in two steps. First, the dielectric permittivity of the equivalent particle is calculated. Afterward, the dielectric permittivity of the polymer−BT nanocomposite, which is determined by the dielectric permittivity of the polymer substrate and the ceramic nanoparticles, is calculated based on the developed Rahaman model. The modeling results are verified using experimental data to evaluate the accuracy of the proposed method. A good agreement between the experimental data and the modeling results can be achieved by properly assuming the characteristics of the interphase. Furthermore, the influences of the BT particle properties, interphase properties, and matrix properties on the dielectric permittivity of polymer−BT nanocomposites are investigated. This developed Rahaman model is expected to provide a theoretical guideline for the experimental design of polymer−BT nanocomposites with excellent dielectric properties.