The electrical resistivity of CB–polymer piezoelectric nanocomposites

Piezoelectric polymer nanocomposites reinforced with conductive particles, such as carbon black (CB), have gained significant attention for their unique combination of mechanical strength and tunable electrical properties. However, accurately predicting the overall electrical conductivity of these materials remains challenging due to the complex interactions between the polymer matrix and conductive nanoparticles, as well as the critical role of interphase regions and tunneling effects. In this study, a modified unit cell model is developed to incorporate interphase conductivity and tunneling resistance, enhancing the accuracy of conductivity predictions. A hierarchical modeling strategy is introduced to capture the synergistic effects of nano- and micro-scale fillers, providing a comprehensive framework for complex composite analysis. The model is validated using CB–KNN–epoxy nanocomposite films, demonstrating strong agreement between numerical predictions and experimental measurements. This work provides valuable insights into the design and optimization of high-performance piezoelectric composites for advanced energy harvesting and flexible electronics.