Polyimide/nanosized CaCu₃Ti₄O₁₂ functional hybrid films with high dielectric permittivity

This work reports the high dielectric permittivity of polyimide (PI) embedded with CaCu₃Ti₄O₁₂ (CCTO) nanoparticles. The dielectric behavior has been investigated over a frequency of 100 Hz-1 MHz. High dielectric permittivity (ε = 171) and low dielectric loss (tan δ = 0.45) at 100 Hz have been observed near the percolation threshold. The experimental results fit well with the Percolation theory. We suggest that the high dielectric permittivity originates from the large interface area and the remarkable Maxwell-Wagner-Sillars effect at percolation in which nomadic charge carriers are blocked at internal interfaces between CCTO nanoparticles and the polyimide matrix.