Dielectric Constant Estimation of Spherical Particle-Filled Nanocomposites Based on the Poon and Shin Model, Considering Interphase Properties.

A revised version of the Poon and Shin (PS) model, incorporating the effects of the interphase, is introduced to predict the dielectric permittivity of polymer nanocomposites reinforced with spherical nanoparticles. In this modified approach, both the spherical nanoparticle and its surrounding interphase region are treated as an equivalent nanoparticle, modeled as a core-shell structure. This assumption enables a more accurate representation of the composite, where the polymer matrix and the equivalent nanoparticles form a homogeneous mixture. The process of calculating the dielectric permittivity of the composite occurs in two distinct steps. Initially, the dielectric permittivity of the equivalent particle-comprising both the nanoparticle core and its interphase-is computed. Subsequently, the overall dielectric permittivity of the composite material is determined, considering the properties of the polymer substrate and the equivalent nanoparticles, all within the framework of the modified PS model. To verify the validity of the proposed model, experimental data are compared against the predicted values, showing a high level of agreement when the interphase characteristics are appropriately incorporated. Additionally, the influence of various factors, including the properties of the spherical nanoparticles, the interphase, and the polymer matrix, on the dielectric performance of the nanocomposite is thoroughly investigated. This enhanced PS model offers a valuable theoretical framework for designing polymer-spherical nanoparticle composites with superior dielectric properties, paving the way for their potential application in advanced electronic and energy storage devices.