Percolative Silver Nanowires/Polyvinylidene Fluoride Epsilon-Negative Materials with Low Losses Derived from the Ultra-Low Percolation Threshold

Abstract

The epsilon-negative materials involving lower losses have attracted increasing attention due to their significant applications in novel capacitors and antennas. The silver nanowires/polyvinylidene fluoride (AgNWs/PVDF) composites were therefore prepared to reveal the mechanism of negative permittivity response involving lower losses. Due to the large aspect ratios of AgNWs, an ultra-low percolation threshold (f_c) between 0.7 and 0.8 wt.% was achieved in which the losses have been effectively decreased with several magnitudes to a low level of 0.2. The negative permittivity response from Lorentz type and Drude type presented the transition from insulator to conductor. The tunable Drude type negative permittivity was ascribed to the plasma oscillation of free electrons which leads to an inductive property. The conduction mechanism was switched from hopping to metallic conduction with the observation of skin effect.

Keywords: metacomposites, negative permittivity, epsilon-negative materials, low losses, silver nanowires