Polymer/metal multi-layers structured composites: A route to high dielectric constant and suppressed dielectric loss

In order to obtain polymer-based composites with a high dielectric constant and suppressed dielectric loss, polyvinylidene fluoride (PVDF)/silver (Ag) multi-layer structured composites were fabricated via vacuum evaporation and hot-press methods. The dielectric constant of the PVDF/Ag(5/4) composite (including five PVDF layers and four Ag layers) is up to 31, and dielectric loss can be suppressed below 0.02 (smaller than that of pure PVDF) at 1 kHz. The enhanced interfacial polarization in multi-layer structured composites is determined via temperature dependence of electrical modulus, which is regarded as the origin of dielectric constant enhancement. The suppressed dielectric loss at low frequency is attributed to the difficulty in the formation of a percolation conductive network in this multi-layer system. This promising multi-layer strategy could be generalized to a variety of polymers to develop polymer-based composites with a high dielectric constant and low dielectric loss.